tty: serial: qcom-geni-serial: Poll primary sequencer irq status after cancel_tx

TX is handled by primary sequencer. After cancelling primary command, poll
primary sequencer's irq status instead of that of secondary.
While at it, also remove a couple of redundant lines that read from IRQ_EN
register and write back same.

Fixes: 2aaa43c7 ("tty: serial: qcom-geni-serial: add support for serial engine DMA")
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Link: https://lore.kernel.org/r/1691578393-9891-1-git-send-email-quic_vnivarth@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>