agx: Enable nir_lower_frexp.

Needed for Vulkan, and for dropping GLSL frontend lowering for the deqp
coverage override case.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22083>

src/asahi/compiler/agx_compile.c

@@ -2325,6 +2325,7 @@ agx_preprocess_nir(nir_shader *nir, bool support_lod_bias)
 
    NIR_PASS_V(nir, nir_lower_regs_to_ssa);
    NIR_PASS_V(nir, nir_lower_idiv, &idiv_options);
+   NIR_PASS_V(nir, nir_lower_frexp);
    NIR_PASS_V(nir, nir_lower_alu_to_scalar, NULL, NULL);
    NIR_PASS_V(nir, nir_lower_load_const_to_scalar);
    NIR_PASS_V(nir, nir_lower_flrp, 16 | 32 | 64, false);