Apply patches from buildroot repos

The goal is to use this version of fbv in buildroot in future. However, before switching, I want to add some available patches: https://github.com/buildroot/buildroot/tree/master/package/fbv

0002-cross.patch
- Patch applied in first commit of this PR
0003-fix-24bpp-support-on-big-endian.patch
- Patch applied in second commit of this PR
0004-fix-bgr555.patch
- Not applied, as I don't understand the reason yet. Currently, I didn't discover any problems without this patch.
0005-giflib.patch
- Not applied, as gif support was removed in this repo
0006-include.patch
- Not applied, as I don't understand the reason for this patch. fbv compiles with no problems without this patch
0007-libpng15.patch
- Not applied, as changes are already included in current fbv version

godspeed1989 / fbv