Avoid namespace collision: rename bswap_XX to radeon_bswap_XX

xorg-server includes its own bswap_16, bswap_32 etc macros in its misc.h. This is transcluded after radeon.h in some files.

If the operating system defines bswap_XX in a way that is unsuitable for a function name (e.g. on NetBSD), this results in build failures.

Signed-off-by: Nia Alarie nia@NetBSD.org