radv: add missing multi inclusion define to radv_shader_args.h

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15794>

src/amd/vulkan/radv_shader_args.h

@@ -21,6 +21,9 @@
  * IN THE SOFTWARE.
  */
 
+#ifndef RADV_SHADER_ARGS_H
+#define RADV_SHADER_ARGS_H
+
 #include "compiler/shader_enums.h"
 #include "util/list.h"
 #include "util/macros.h"
@@ -70,3 +73,5 @@ void radv_declare_shader_args(enum chip_class chip_class, const struct radv_pipe
                               const struct radv_shader_info *info, gl_shader_stage stage,
                               bool has_previous_stage, gl_shader_stage previous_stage,
                               struct radv_shader_args *args);
+
+#endif