i965/fs: Fix 32-bit integer multiplication.

The MUL opcode does a 16bit * 32bit multiply, and we need to do the
MACH to get the top 16bit * 32bit added in.

Fixes fs-op-mult-int-*, fs-op-mult-ivec*

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
2 files changed