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 <[e-mail]>
Reported-by: Maxim Kochetkov <[e-mail]>
Fixes: dc56ecb81a0a ("serial: 8250: Support disabling mdelay-filled probes of 16550A variants")
Cc: stable <[e-mail]>
Signed-off-by: Josh Triplett <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/8250/Kconfig

···
 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.