octeontx2-pf: Disable packet I/O for graceful exit

At the stage of enabling packet I/O in otx2_open, If mailbox
timeout occurs then interface ends up in down state where as
hardware packet I/O is enabled. Hence disable packet I/O also
before bailing out.

Fixes: 1ea0166d ("octeontx2-pf: Fix the device state on error")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>