If SERIAL_8250_RUNTIME_UARTS is > SERIAL_8250_NR_UARTS then more serial
ports are registered than we've allocated memory for.  Prevent this by
limiting SERIAL_8250_RUNTIME_UARTS in the serial Kconfig.

Signed-off-by: David Vrabel <dvrabel@arcom.com>
-- 
David Vrabel, Design Engineer

Arcom, Clifton Road           Tel: +44 (0)1223 411200 ext. 3233
Cambridge CB1 7EA, UK         Web: http://www.arcom.com/