build: add sha1_h for lp_texture.c
Fixes:
../mesa-9999/src/gallium/drivers/llvmpipe/lp_texture.c:55:10: fatal error: git_sha1.h: No such file or directory
Fixes:
../mesa-9999/src/gallium/drivers/llvmpipe/lp_texture.c:55:10: fatal error: git_sha1.h: No such file or directory