bmp loader: Fix loading of monochrome/greyscale BMPs with newer headers.

The code expected the color table at offset 54 (14+size of BITMAPINFOHEADER),
which was after the BITMAPINFOHEADER header. However, newer BITMAPINFOHEADER
versions exist which have more fields before the color table. Fix this by
explicitely seeking to the color table.

Change-Id: If1dfc77e7485e5a9e0bc0e7f577152da9358bd71
1 file changed