serial: 8250: Enable 16550A variants by default on non-x86

Some embedded devices still use these serial ports; make sure they're
still enabled by default on architectures more likely to have them, to
avoid rendering someone's console unavailable.
Reported-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reported-by: Maxim Kochetkov <fido_max@inbox.ru>
Fixes: dc56ecb8 ("serial: 8250: Support disabling mdelay-filled probes of 16550A variants")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/a20b5fb7dd295cfb48160eecf4bdebd76332d67d.1590509426.git.josh@joshtriplett.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/Kconfig

@@ -63,6 +63,7 @@ config SERIAL_8250_PNP
 config SERIAL_8250_16550A_VARIANTS
 	bool "Support for variants of the 16550A serial port"
 	depends on SERIAL_8250
+	default !X86
 	help
 	  The 8250 driver can probe for many variants of the venerable 16550A
 	  serial port. Doing so takes additional time at boot.