[ARM] S3C: Update CONFIG_SERIAL_SAMSUNG_UARTS handling

Fix the usage of CONFIG_SERIAL_SAMSUNG_UARTS in several places
in the kernel where it had been missed. This finishes fixing a
long standing issue where S3C2443 and S3C64XX could not use the
4th UART

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

arch/arm/plat-s3c/init.c

@@ -91,7 +91,7 @@ void __init s3c24xx_init_clocks(int xtal)
 
 static int nr_uarts __initdata = 0;
 
-static struct s3c2410_uartcfg uart_cfgs[3];
+static struct s3c2410_uartcfg uart_cfgs[CONFIG_SERIAL_SAMSUNG_UARTS];
 
 /* s3c24xx_init_uartdevs
  *