r600: Replace R600_BIG_ENDIAN with UTIL_ARCH_BIG_ENDIAN
Removes the dependency of r600_formats.h
on r600_pipe.h
so it can be shared between Gallium and Vulkan.
Setting R600_BIG_ENDIAN
to a value different than the host endianness is largely meaningless, I think, as it would cause the data passed by the host to become completely wrong.
Edited by Triang3l (Vitaliy Kuzmin)