[SCSI] zfcp: fix module parameter parsing

From: Heiko Carstens <heiko.carstens@de.ibm.com>

Fixes module parameter parsing for "device" parameter.  The original
module parameter was changed while parsing it.  This corrupted the
output in sysfs (/sys/module/zfcp/parameters/device).

Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>