net/mlx5_core: Set log_uar_page_sz for non 4K page size architecture

failed to configure the page size for architectures with page size
different than 4K.

Fixes: 938fe83c

 ("net/mlx5_core: New device capabilities handling")
Signed-off-by: Carol L Soto <clsoto@linux.vnet.ibm.com>
Acked-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>