bootstage: Show func name for bootstage_mark/error

bootstage: Show func name for bootstage_mark/error

bootstage_mark() and bootstate_error() are not recording any name and in
report it is showing as id=<value>. That's not useful and it is better to
show function name which calls it.
That's why use macros with passing __func__ as recorded name for bootstage.

Origin report looks like this:
ZynqMP> bootstage report
Timer summary in microseconds (10 records):
       Mark    Elapsed  Stage
          0          0  reset
  2,482,383  2,482,383  board_init_f
  4,278,821  1,796,438  board_init_r
  4,825,331    546,510  id=64
  4,858,409     33,078  id=65
  4,862,382      3,973  main_loop
  4,921,713     59,331  usb_start
  9,345,345  4,423,632  id=175

When this patch is applied.
ZynqMP> bootstage report
Timer summary in microseconds (31 records):
       Mark    Elapsed  Stage
          0          0  reset
  2,465,624  2,465,624  board_init_f
  4,278,628  1,813,004  board_init_r
  4,825,139    546,511  eth_common_init
  4,858,228     33,089  eth_initialize
  4,862,201      3,973  main_loop
  4,921,530     59,329  usb_start
  8,885,334  3,963,804  cli_loop

Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Simon Glass <sjg@chromium.org>