Clean up some Kconfig entries.

[PATCH 1/4 v2] serial: imx: change SERIAL_IMX_CONSOLE to bool
[PATCH 2/4 v2] serial: 8250: fix ordering of entries for menu display
[PATCH 3/4 v2] serial: Kconfig: fix ordering of entries for menu display
[PATCH 4/4 v2] serial: SH_SCI: improve "DMA support" prompt

Patches 1-3 are the same as v1 other than dropping
Fugang Duan <fugang.duan@nxp.com> from patch 1/4 (mail bounces).

Patch 4 was modified at Geert's request.

 drivers/tty/serial/8250/Kconfig |   95 +++++++++++++++---------------
 drivers/tty/serial/Kconfig      |   34 +++++-----
 2 files changed, 65 insertions(+), 64 deletions(-)

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: linux-serial@vger.kernel.org