Add an option to strip leading zeros from linear histograms

Add an option to strip leading zeros from linear histograms

Sometimes histogram gives us too much zero info that we don't really care.

For example:
      usec         : count     distribution
        0          : 0        |                                        |
        1          : 0        |                                        |
        2          : 0        |                                        |
        3          : 0        |                                        |
        4          : 0        |                                        |
        5          : 0        |                                        |
        6          : 0        |                                        |
        7          : 0        |                                        |
        8          : 0        |                                        |
        9          : 0        |                                        |
        10         : 0        |                                        |
        11         : 0        |                                        |
        12         : 0        |                                        |
        13         : 0        |                                        |
        14         : 0        |                                        |
        15         : 0        |                                        |
        16         : 0        |                                        |
        17         : 0        |                                        |
        18         : 0        |                                        |
        19         : 0        |                                        |
        20         : 0        |                                        |
        21         : 0        |                                        |
        22         : 0        |                                        |
        23         : 0        |                                        |
        24         : 0        |                                        |
        25         : 0        |                                        |
        26         : 0        |                                        |
        27         : 0        |                                        |
        28         : 0        |                                        |
        29         : 0        |                                        |
        30         : 0        |                                        |
        31         : 0        |                                        |
        32         : 0        |                                        |
        33         : 0        |                                        |
        34         : 0        |                                        |
        35         : 0        |                                        |
        36         : 0        |                                        |
        37         : 0        |                                        |
        38         : 0        |                                        |
        39         : 0        |                                        |
        40         : 0        |                                        |
        41         : 7        |****************************************|
        42         : 2        |***********                             |

Such much info is hard to analyze by FIRST glance, especially console view

After supporting strip leading zeros
print_linear_hist("usec", "name", name_print, strip_leading_zero=True)

      usec         : count     distribution
        41         : 7        |****************************************|
        42         : 2        |*************                           |

This is what we really care, and it's clear.

Signed-off-by: Edward Wu <edwardwu@realtek.com>