cxl/hdm: Debug, use decoder name function

The decoder enum has a name conversion function defined now.

Use that instead of open coding.
Suggested-by: Navneet Singh <navneet.singh@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20230604-dcd-type2-upstream-v2-1-f740c47e7916@intel.comSigned-off-by: Dave Jiang <dave.jiang@intel.com>

drivers/cxl/core/hdm.c

@@ -519,8 +519,7 @@ int cxl_dpa_alloc(struct cxl_endpoint_decoder *cxled, unsigned long long size)
 
 	if (size > avail) {
 		dev_dbg(dev, "%pa exceeds available %s capacity: %pa\n", &size,
-			cxled->mode == CXL_DECODER_RAM ? "ram" : "pmem",
-			&avail);
+			cxl_decoder_mode_name(cxled->mode), &avail);
 		rc = -ENOSPC;
 		goto out;
 	}