tty: n_gsm: clean up indenting in gsm_queue()

These two lines need to be indented one more tab.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20211004104343.GF25015@kiliSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>