msm_serial_hs: Fix Tx path issues during uart shutdown

UART queues tx transfer request to ADM and upon getting completion
callback from ADM, schedules tx tasklet in which it enables the
Tx Ready Interrupt and waits for it. On Tx ready interrupt tx
dma_in_flight is set to zero indicating no more tx data is pending.

This would cause corner case where if uart shutdown function checks
dma_in_flight flag between dmov callback and Tx Ready interrupt,
then this may cause uart shutdown function queuing dmov flush for
the completed Tx command and with this dmov flush callback never
be called. To fix this issue, move the dma_in_flight flag reset from
Tx Ready interrupt to dmov callback.

To avoid issues if any uart clients submitting any Tx requests after
uart shutdown, add is_shutdown flag and check before tx command
submission.

CRs-Fixed: 476745
Change-Id: Ibeddbe24e9f4047ecc4871555ddf35fecdfde8d5
Signed-off-by: Saket Saurabh <ssaurabh@codeaurora.org>

Conflicts:
	drivers/tty/serial/msm_serial_hs.c
msm_serial_hs: Fix UART Rx dmov command stall issues

Resetting Rx and Tx HW state machine while Rx dmov command queued
with ADM, caused dmov stall issues. Hence moving the Rx and Tx reset
to after dmov_flush. In order to do this, change the Rx path to not
enqueue dmov request as a part of dmov flush when flush is
FLUSH_IGNORE.

Removing the unnecessary UART Rx and Tx HW Reset in
msm_hs_set_bps_locked().

Require to add few clock cycles after Rx and Tx HW reset, hence
adding 10us delay as safe side. In addition to this, combining
both Rx and Tx reset in single register write.

CRs-Fixed: 481244
Change-Id: I5f181f416b8e66af689c77c4abd48131dedd32d1
Signed-off-by: Saket Saurabh <ssaurabh@codeaurora.org>