scsi: ufs: Add support for sending NOP OUT UPIU

As part of device initialization sequence, sending NOP OUT UPIU and
waiting for NOP IN UPIU response is mandatory. This confirms that the
device UFS Transport (UTP) layer is functional and the host can configure
the device with further commands. Add support for sending NOP OUT UPIU to
check the device connection path and test whether the UTP layer on the
device side is functional during initialization.

A tag is acquired from the SCSI tag map space in order to send the device
management command. When the tag is acquired by internal command the scsi
command is rejected with host busy flag in order to requeue the request.
To avoid frequent collisions between internal commands and scsi commands
the device management command tag is allocated in the opposite direction
w.r.t block layer tag allocation.

Change-Id: I57702fd241aaf141ee5638ccda636851eb608e73
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>