[SCSI] qla2xxx: correct locking while call starget_for_each_device()

Removed spin_unlock_irq()/spin_lock_irq() pairs surrounding
starget_for_each_device() calls.
As Matthew W. pointed out, starget_for_each_device() can be called under
a spinlock being held.
The change has been tested and verified on qla2xxx.ko module.
Thanks Matthew W. and Hisashi H. for help.

Signed-off-by: Andrew Vasquez <Andrew.vasquez@qlogic.com>
Signed-off-by: Seokmann Ju <Seokmann.ju@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>