agx: enable bitfield lowering for cl_khr_extended_bit_ops

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35448>

src/asahi/compiler/agx_compile.c

@@ -3341,6 +3341,14 @@ lower_bit_size_callback(const nir_instr *instr, UNUSED void *_)
        * implemented natively.
        */
       nir_alu_instr *alu = nir_instr_as_alu(instr);
+
+      switch (alu->op) {
+      case nir_op_bitfield_reverse:
+         return alu->def.bit_size < 32 ? 32 : 0;
+      default:
+         break;
+      }
+
       if (alu->def.bit_size == 8 && !is_conversion_to_8bit(alu->op))
          return 16;
       else if (alu->def.bit_size == 1 && alu->src[0].src.ssa->bit_size == 8)

src/asahi/compiler/agx_compile.h

@@ -335,6 +335,8 @@ static const nir_shader_compiler_options agx_nir_options = {
    .lower_flrp32 = true,
    .lower_fpow = true,
    .lower_fmod = true,
+   .lower_bitfield_extract8 = true,
+   .lower_bitfield_extract16 = true,
    .lower_bitfield_insert = true,
    .lower_ifind_msb = true,
    .lower_find_lsb = true,