[SCSI] ufs: don't disable_irq() if the IRQ can be shared among devices

When removing the UFS driver, disable_irq() is called and the IRQ is
not enabled again.  Unfortunately, the IRQ is requested with IRQF_SHARED
and it can be shared among several devices.  So disabling the IRQ in
this way is just breaking other devices which are sharing the IRQ.

Signed-off-by: Akinobu Mita <mita@fixstars.com>
Signed-off-by: Santosh Y <santoshsy@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>