net/mlx5: Ensure SRQ physical address structure endianness

SRQ physical address structure field should be in big-endian format.

Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>