net: marvell: prestera: disable events interrupt while handling

There are change in firmware which requires that receiver will
disable event interrupts before handling them and enable them
after finish with handling. Events still may come into the queue
but without receiver interruption.

Signed-off-by: Vadym Kochan <vkochan@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>