When ioread32() returns 0xFFFFFFFF, we should execute cleanup functions
like other error handling paths before returning.

Link: https://lore.kernel.org/r/20201225083520.22015-1-dinghao.liu@zju.edu.cnAcked-by: Karan Tilak Kumar <kartilak@cisco.com>
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>