scsi: ufs: make sure all interrupts are processed

[ Upstream commit 7f6ba4f12e6cbfdefbb95cfd8fc67ece6c15d799 ]

As multiple requests are submitted to the ufs host controller in
parallel there could be instances where the command completion interrupt
arrives later for a request that is already processed earlier as the
corresponding doorbell was cleared when handling the previous
interrupt. Read the interrupt status in a loop after processing the
received interrupt to catch such interrupts and handle it.

Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>