bootsplash: Added support for 16/24/32bpp in one function

bootsplash: Added support for 16/24/32bpp in one function

Specifically added support for 16 and 32bpp files, in addition to
24bpp.  The function bmp_show() in bmp.c has had the hardcoded check
for 24bpp replaced with a general bpp check that uses a % to check for
remainder, and returns 1 if the remainder is >0.  The previous method
for adjusting the BMP data (raw_data_format_adjust_24bpp) relied on a
preset 3*bytes_per_line_src, this has been changed and the
multiplication is now performed in the function's arguments. This
change still allows someone else to reuse the same function for
1/2/4bpp support if necessary. The file util.h has been modified to
reflect this decision.

The changes to raw_data_format_adjust() is based on an abandoned patch
by Gert Menke (submitted March 14, 2017), credit to them for that
change and the addition of *bpp to bmp_get_info().

Signed-off-by: Joseph S. Pacheco-Corwin <hammersamatom@gmail.com>