tty: n_gsm: clean up dead code in gsm_queue()

Remove commented out code as it is never used and if anyone accidentally
turned it on, it would be broken.

Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220420101346.3315-2-daniel.starke@siemens.com


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