scsi: qla4xxx: Prevent a potential error pointer dereference

scsi: qla4xxx: Prevent a potential error pointer dereference

The qla4xxx_get_ep_fwdb() function is supposed to return NULL on error,
but qla4xxx_ep_connect() returns error pointers.  Propagating the error
pointers will lead to an Oops in the caller, so change the error pointers
to NULL.

Fixes: 13483730a13b ("[SCSI] qla4xxx: fix flash/ddb support")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/aJwnVKS9tHsw1tEu@stanley.mountain
Reviewed-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>