cxl/mem: Skip range enumeration if mem_enable clear

When a device does not have mem_enable set then the current range
settings are moot. Skip the enumeration and cause cxl_hdm_decode_init()
to proceed directly to enable the HDM Decoder Capability.

Fixes: 560f785590 ("cxl/pci: Retrieve CXL DVSEC memory info")
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165291689442.1426646.18012291761753694336.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/pci.c

@@ -224,6 +224,8 @@ int cxl_dvsec_ranges(struct cxl_dev_state *cxlds,
 	}
 
 	info->mem_enabled = FIELD_GET(CXL_DVSEC_MEM_ENABLE, ctrl);
+	if (!info->mem_enabled)
+		return 0;
 
 	for (i = 0; i < hdm_count; i++) {
 		u64 base, size;

drivers/cxl/mem.c

@@ -92,7 +92,7 @@ __mock bool cxl_hdm_decode_init(struct cxl_dev_state *cxlds,
 	 * are expected even though Linux does not require or maintain that
 	 * match.
 	 */
-	if (!global_enable && info->ranges)
+	if (!global_enable && info->mem_enabled && info->ranges)
 		goto out;
 
 	retval = true;