anv: remove unneeded extern C notation

Analogous to previous commit - never used in any C++ code.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/intel/vulkan/anv_private.h

@@ -68,10 +68,6 @@ struct gen_l3_config;
 
 #include "wsi_common.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* Allowing different clear colors requires us to perform a depth resolve at
  * the end of certain render passes. This is because while slow clears store
  * the clear color in the HiZ buffer, fast clears (without a resolve) don't.
@@ -1971,8 +1967,4 @@ ANV_DEFINE_NONDISP_HANDLE_CASTS(anv_shader_module, VkShaderModule)
 #  undef genX
 #endif
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* ANV_PRIVATE_H */