drm/armada: add extern C guard for the UAPI header

Signed-off-by: NEmil Velikov <emil.l.velikov@gmail.com>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>

include/uapi/drm/armada_drm.h

@@ -11,6 +11,10 @@
 
 #include "drm.h"
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 #define DRM_ARMADA_GEM_CREATE		0x00
 #define DRM_ARMADA_GEM_MMAP		0x02
 #define DRM_ARMADA_GEM_PWRITE		0x03
@@ -44,4 +48,8 @@ struct drm_armada_gem_pwrite {
 #define DRM_IOCTL_ARMADA_GEM_PWRITE \
 	ARMADA_IOCTL(IOW, GEM_PWRITE, gem_pwrite)
 
+#if defined(__cplusplus)
+}
+#endif
+
 #endif