lima/ppir: enable vectorize optimization

pp has vector units and some operations can be optimized when bundled
together.
Benchmarking this with piglit shaders shows that the instruction count
can be greatly reduced on many examples with vectorize.

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Reviewed-by: Qiang Yu <yuq825@gmail.com>

src/gallium/drivers/lima/lima_program.c

@@ -169,6 +169,11 @@ lima_program_optimize_fs_nir(struct nir_shader *s)
    NIR_PASS_V(s, nir_lower_regs_to_ssa);
    NIR_PASS_V(s, nir_lower_tex, &tex_options);
 
+   do {
+      progress = false;
+      NIR_PASS(progress, s, nir_opt_vectorize);
+   } while (progress);
+
    do {
       progress = false;