scsi: ufs: core: Cancel RTC work during ufshcd_remove()

In the Linux kernel, the following vulnerability has been resolved:

scsi: ufs: core: Cancel RTC work during ufshcd_remove()

Currently, RTC work is only cancelled during __ufshcd_wl_suspend(). When

ufshcd is removed in ufshcd_remove(), RTC work is not cancelled. Due to

this, any further trigger of the RTC work after ufshcd_remove() would

result in a NULL pointer dereference as below:

Unable to handle kernel NULL pointer dereference at virtual address 00000000000002a4

Workqueue: events ufshcd_rtc_work

Call trace:

_raw_spin_lock_irqsave+0x34/0x8c

pm_runtime_get_if_active+0x24/0xb4

ufshcd_rtc_work+0x124/0x19c

process_scheduled_works+0x18c/0x2d8

worker_thread+0x144/0x280

kthread+0x11c/0x128

ret_from_fork+0x10/0x20

Since RTC work accesses the ufshcd internal structures, it should be cancelled

when ufshcd is removed. So do that in ufshcd_remove(), as per the order in

ufshcd_init().