intel/compiler: activate 16-bit bit-size lowerings also for 8-bit

Particularly, we need the same lowewrings we use for 16-bit
integers.

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

src/intel/compiler/brw_nir.c

@@ -628,7 +628,7 @@ static unsigned
 lower_bit_size_callback(const nir_alu_instr *alu, UNUSED void *data)
 {
    assert(alu->dest.dest.is_ssa);
-   if (alu->dest.dest.ssa.bit_size != 16)
+   if (alu->dest.dest.ssa.bit_size >= 32)
       return 0;
 
    const struct brw_compiler *compiler = (const struct brw_compiler *) data;