nvme: add Metadata Capabilities enumerations

The enumerations will be used to expose the namespace metadata format by
the target.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

include/linux/nvme.h

@@ -420,6 +420,12 @@ enum {
 	NVME_NS_DPS_PI_TYPE3	= 3,
 };
 
+/* Identify Namespace Metadata Capabilities (MC): */
+enum {
+	NVME_MC_EXTENDED_LBA	= (1 << 0),
+	NVME_MC_METADATA_PTR	= (1 << 1),
+};
+
 struct nvme_ns_id_desc {
 	__u8 nidt;
 	__u8 nidl;