drm/amdgpu: suppress some compile warnings

Suppress two compile warnings about "no previous prototype".
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c

@@ -1361,7 +1361,7 @@ union mall_info {
 	struct mall_info_v1_0 v1;
 };
 
-int amdgpu_discovery_get_mall_info(struct amdgpu_device *adev)
+static int amdgpu_discovery_get_mall_info(struct amdgpu_device *adev)
 {
 	struct binary_header *bhdr;
 	union mall_info *mall_info;

drivers/gpu/drm/amd/amdgpu/soc21.c

@@ -42,6 +42,7 @@
 
 #include "soc15.h"
 #include "soc15_common.h"
+#include "soc21.h"
 
 static const struct amd_ip_funcs soc21_common_ip_funcs;