Shifting into the sign bit of a signed int is undefined behavior.
Unfortunately, there are potentially many places where this happens using
the register macros.

This commit is the result of running

sed -ie "s/(((\(\w\+\)) & 0x\(\w\+\)) << \(\w\+\))/(((unsigned)(\1) \& 0x\2) << \3)/g"

on all header files in gallium/{r600,radeon,radeonsi}.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>