radeonsi/ac: move vertex export remove to common code.

This code can be shared by radv, we bump the max to
VARYING_SLOT_MAX here, but that shouldn't have too
much fallout.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/amd/common/ac_llvm_build.h

@@ -239,6 +239,12 @@ void ac_get_image_intr_name(const char *base_name,
 			    LLVMTypeRef coords_type,
 			    LLVMTypeRef rsrc_type,
 			    char *out_name, unsigned out_len);
+
+void ac_eliminate_const_vs_outputs(struct ac_llvm_context *ac,
+				   LLVMValueRef main_fn,
+				   uint8_t *vs_output_param_offset,
+				   uint32_t num_outputs,
+				   uint8_t *num_param_exports);
 #ifdef __cplusplus
 }
 #endif