nir: Add a pass to inline functions

This commit adds a new NIR pass that lowers all function calls away by
inlining the functions.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

src/compiler/nir/nir.h

@@ -2149,6 +2149,8 @@ bool nir_split_var_copies(nir_shader *shader);
 bool nir_lower_returns_impl(nir_function_impl *impl);
 bool nir_lower_returns(nir_shader *shader);
 
+bool nir_inline_functions(nir_shader *shader);
+
 void nir_lower_var_copy_instr(nir_intrinsic_instr *copy, void *mem_ctx);
 void nir_lower_var_copies(nir_shader *shader);