glsl: Bitwise conversion operator support in the software renderers.

glsl: Bitwise conversion operator support in the software renderers.

TGSI doesn't need an opcode, since registers are untyped (but beware
once doubles come into the scene).  Mesa IR doesn't handle native
integers, so trying to handle them there is worthless, the case
entries are only added for warning reasons.

It was only tested with softpipe, since llvmpipe doesn't support glsl
1.3 yet.

Signed-off-by: Olivier Galibert <galibert@pobox.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>