cxl/region: Only warn about cpu_cache_invalidate_memregion() once

No need for more than once per module load.
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20221215183836.24136-1-dave@stgolabs.netSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/region.c

@@ -1967,7 +1967,7 @@ static int cxl_region_invalidate_memregion(struct cxl_region *cxlr)
 
 	if (!cpu_cache_has_invalidate_memregion()) {
 		if (IS_ENABLED(CONFIG_CXL_REGION_INVALIDATION_TEST)) {
-			dev_warn(
+			dev_warn_once(
 				&cxlr->dev,
 				"Bypassing cpu_cache_invalidate_memregion() for testing!\n");
 			clear_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags);