serial: qcom-geni: fix polled console initialisation

The polled console (KGDB/KDB) implementation must not call port setup
unconditionally as the port may already be in use by the console or a
getty.

Only make sure that the receiver is enabled, but do not enable any
device interrupts.

Fixes: d8851a96 ("tty: serial: qcom-geni-serial: Add a poll_init() function")
Cc: stable@vger.kernel.org	# 6.4
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20241009145110.16847-2-johan+linaro@kernel.org


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