serial: msm_geni: Cancel/fail transmits if TX state machine is not valid

In some cases it is possible that the TX state machine is not valid.
Attempting to wait for the watermark interrupt before writing to the Tx
FIFO could cause the system to lock-up, instead bail if the watermark
interrupt doesn't set and try to reset the TX sequencer.
Also at bootup issue an unconditional cancel/abort on the TX sequencer in
a bid to clear the state machine and issue an abort on the RX sequencer if
it claims to be active.

Change-Id: I5ad3fcbd82e1a65c4b408fde8b3bfe332ef8aa83
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>