Driver uses the Firmware mailbox to read statistics and configure
some features.
This patch introduces a mutex to provide consistent access to the
FW mailbox to prevent potential data corruption.
Fixes: 86d36773bd ("net/atlantic: implement firmware operations")
Cc: stable@dpdk.org
Signed-off-by: Pavel Belous <pavel.belous@aquantia.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>