IB/uverbs: Expose device memory capabilities to user

Adding a new capability field under ib_uverbs_ex_query_device_resp -
max_dm_size - which reflects the maximum amount of device memory
that is available for allocation on a device in bytes.

Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

include/uapi/rdma/ib_user_verbs.h

@@ -268,6 +268,7 @@ struct ib_uverbs_ex_query_device_resp {
 	__u32 raw_packet_caps;
 	struct ib_uverbs_tm_caps tm_caps;
 	struct ib_uverbs_cq_moderation_caps cq_moderation_caps;
+	__aligned_u64 max_dm_size;
 };
 
 struct ib_uverbs_query_port {