With recent update in u-boot gitattributes all files are treated as regular
text files. This creates problems with special files and repo always
shows uncommitted files like below.

Your branch is up-to-date with 'origin/master'.
Changes not staged for commit:
(use "git add ..." to update what will be committed)
(use "git checkout -- ..." to discard changes in working directory)

modified: tools/logos/compulab.bmp
modified: tools/logos/denx-comp.bmp
modified: tools/logos/toradex.bmp

To fix above problem special files bmp/ttf files are treated as binary
files in the gitattributes.

Signed-off-by: Vignesh Rajendran
Signed-off-by: Veeraiyan Chidambaram