i965: Add do32 debug option.

The do32 INTEL_DEBUG option causes the back-end to try to generate a
SIMD32 program when compiling a compute shader regardless of the
specified compute shader workgroup size, which will be useful for
testing SIMD32 code generation in the most common case in which the
workgroup size doesn't exceed the SIMD16 limit so SIMD32 codegen
wouldn't be automatically enabled.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/mesa/drivers/dri/i965/intel_debug.c

@@ -79,6 +79,7 @@ static const struct debug_control debug_control[] = {
    { "ds",          DEBUG_TES },
    { "tes",         DEBUG_TES },
    { "l3",          DEBUG_L3 },
+   { "do32",        DEBUG_DO32 },
    { NULL,    0 }
 };