Currently driver waits for the command IOCTL from the firmware and if the
firmware enters nonresponsive state, the driver doesn't respond till the
firmware is responsive again.

Check that firmware is alive, otherwise return -EBUSY.

[mkp: clarified commit desc]

Link: https://lore.kernel.org/r/1571120524-6037-6-git-send-email-balsundar.p@microsemi.comSigned-off-by: Balsundar P <balsundar.p@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>