radv: Don't run opt_remove_phis before lower_returns

nir_lower_returns will run nir_opt_remove_phis as part of its work

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Friedrich Vock <friedrich.vock@gmx.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22913>

src/amd/vulkan/radv_rt_shader.c

@@ -832,7 +832,6 @@ insert_rt_case(nir_builder *b, nir_shader *shader, struct rt_variables *vars, ni
 
    NIR_PASS_V(shader, lower_rt_instructions, &src_vars, call_idx_base);
 
-   NIR_PASS(_, shader, nir_opt_remove_phis);
    NIR_PASS(_, shader, nir_lower_returns);
    NIR_PASS(_, shader, nir_opt_dce);