ac: add missing extern "C" guards

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/amd/common/ac_gpu_info.h

@@ -30,6 +30,10 @@
 
 #include <amdgpu.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct radeon_info {
 	/* PCI info: domain:bus:dev:func */
 	uint32_t                    pci_domain;
@@ -95,4 +99,8 @@ bool ac_query_gpu_info(int fd, amdgpu_device_handle dev,
 		       struct radeon_info *info,
 		       struct amdgpu_gpu_info *amdinfo);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* AC_GPU_INFO_H */

src/amd/common/ac_surface.h

@@ -30,6 +30,10 @@
 
 #include "amd_family.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Forward declarations. */
 typedef void* ADDR_HANDLE;
 
@@ -208,4 +212,8 @@ int ac_compute_surface(ADDR_HANDLE addrlib, const struct radeon_info *info,
 		       enum radeon_surf_mode mode,
 		       struct radeon_surf *surf);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* AC_SURFACE_H */