i965: Silence GCC maybe-uninitialized warning.
i965: Silence GCC maybe-uninitialized warning.

brw_shader.cpp: In function ‘bool brw_saturate_immediate(brw_reg_type, brw_reg*)’:
brw_shader.cpp:618:31: warning: ‘sat_imm.brw_saturate_immediate(brw_reg_type, brw_reg*)::<anonymous union>::ud’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       reg->dw1.ud = sat_imm.ud;
                               ^

Signed-off-by: Vinson Lee <25a259f709b0f1b620605d2518271a846d8826e5@freedesktop.org>
Reviewed-by: Anuj Phogat <e2026475996c48f0b97fd37e84129b3912980428@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler