drm/rockchip: fix spelling mistake "modifer" -> "modifier"

There is a spelling mistake in a DRM_DEBUG_KMS debug message. Fix it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200415083420.366279-1-colin.king@canonical.com

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

@@ -769,7 +769,7 @@ static bool rockchip_mod_supported(struct drm_plane *plane,
 		return true;
 
 	if (!rockchip_afbc(modifier)) {
-		DRM_DEBUG_KMS("Unsupported format modifer 0x%llx\n", modifier);
+		DRM_DEBUG_KMS("Unsupported format modifier 0x%llx\n", modifier);
 
 		return false;
 	}