Remove the use of no-op B16 & B32 bitfield macros in headers

These have always done nothing on all platforms except CRAY.
As https://bugs.freedesktop.org/show_bug.cgi?id=45202

 points out
we don't even detect when they've been wrong for decades.

Performed via:
find include -name '*.h' | grep -v md.h | xargs perl -i -p -e 's{\s+B\d+}{}g'
followed by manual whitespace fixups to preserve visual alignment.

The #defines for B16 & B32 are left in place to preserve compatibility
in any code that used them outside the xorgproto repo.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Acked-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>