serial: imx: do not sysrq broken chars

Do not call uart_handle_sysrq_char() if we got any receive error along with
the character, as we don't want random junk to be considered a sysrq.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/20230201142700.4346-4-sorganov@gmail.com


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