Avoid dropping into shell if the controller is in locked up state.

Driver issues SIS soft reset to bring back the controller to SIS mode while
OS boots into kdump mode.

If the controller is in lockup state, SIS soft reset does not work.

Since the controller lockup code has not been cleared, driver considers the
firmware is no longer up and running. Driver returns back an error code to
OS and the kdump fails.

Link: https://lore.kernel.org/r/164375212337.440833.11955356190354940369.stgit@brunhilda.pdev.netReviewed-by: NKevin Barnett <kevin.barnett@microchip.com>
Reviewed-by: NScott Benesh <scott.benesh@microchip.com>
Reviewed-by: NScott Teel <scott.teel@microchip.com>
Signed-off-by: NMahesh Rajashekhara <mahesh.rajashekhara@microchip.com>
Signed-off-by: NDon Brace <don.brace@microchip.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>