common: lcd: extend lcd api by function lcd_get_position_cursor()

common: lcd: extend lcd api by function lcd_get_position_cursor()

This commit change the name of function lcd_position_cursor()
to lcd_set_position_cursor() and adds its complementary function
lcd_get_position_cursor().
This change is useful e.g. when user wants overwrite some lines,
words or even just a letter on lcd console screen.

Other changes:
- update previous lcd_position_cursor() calls

Change-Id: I4a102c236f2d2d5c238e9790382e4b9454e3c361
Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Vadim Bendebury <vbendeb@chromium.org>
Cc: Simon Glass <sjg@chromium.org>