scsi: 3ware: fix return 0 on the error path of probe

tw_probe() returns 0 in case of fail of tw_initialize_device_extension(),
pci_resource_start() or tw_reset_sequence() and releases resources.
twl_probe() returns 0 in case of fail of twl_initialize_device_extension(),
pci_iomap() and twl_reset_sequence().  twa_probe() returns 0 in case of
fail of tw_initialize_device_extension(), ioremap() and
twa_reset_sequence().

The patch adds retval initialization for these cases.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Acked-by: Adam Radford <aradford@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>