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

Cc: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>

include/uapi/drm/tegra_drm.h

@@ -25,6 +25,10 @@
 
 #include "drm.h"
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 #define DRM_TEGRA_GEM_CREATE_TILED     (1 << 0)
 #define DRM_TEGRA_GEM_CREATE_BOTTOM_UP (1 << 1)
 
@@ -198,4 +202,8 @@ struct drm_tegra_gem_get_flags {
 #define DRM_IOCTL_TEGRA_GEM_SET_FLAGS DRM_IOWR(DRM_COMMAND_BASE + DRM_TEGRA_GEM_SET_FLAGS, struct drm_tegra_gem_set_flags)
 #define DRM_IOCTL_TEGRA_GEM_GET_FLAGS DRM_IOWR(DRM_COMMAND_BASE + DRM_TEGRA_GEM_GET_FLAGS, struct drm_tegra_gem_get_flags)
 
+#if defined(__cplusplus)
+}
+#endif
+
 #endif