RDMA/efa: Store network attributes in device attributes

There's no reason to separate the network attributes from all other
device attributes. Embed the fields inside the device attributes and
query them all in one function.

Link: https://lore.kernel.org/r/20191121141509.59297-2-galpress@amazon.com
Reviewed-by: Daniel Kranzdorf <dkkranzd@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/efa/efa.h

@@ -60,8 +60,6 @@ struct efa_dev {
 	u64 mem_bar_len;
 	u64 db_bar_addr;
 	u64 db_bar_len;
-	u8 addr[EFA_GID_SIZE];
-	u32 mtu;
 
 	int admin_msix_vector_idx;
 	struct efa_irq admin_irq;