ARM: SAMSUNG: Replace inclusion of plat/regs-serial.h header file

regs-serial.h only includes linux/serial_s3c.h. Include this header
directly to remove unnecessary platform dependency.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
[broonie@linaro.org: Acked for S3C64XX related changes]
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-s3c24xx/mach-at2440evb.c

@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/serial_core.h>
+#include <linux/serial_s3c.h>
 #include <linux/dm9000.h>
 #include <linux/platform_device.h>
 
@@ -33,7 +34,6 @@
 #include <asm/irq.h>
 #include <asm/mach-types.h>
 
-#include <plat/regs-serial.h>
 #include <mach/regs-gpio.h>
 #include <mach/regs-lcd.h>
 #include <mach/gpio-samsung.h>