Use resource_size_t for serial port IO addresses

At present, various parts of the serial code use unsigned long to define
resource addresses.  This is a problem, because some 32-bit platforms have
physical addresses larger than 32-bits, and have mmio serial uarts located
above the 4GB point.

This patch changes the type of mapbase in both struct uart_port and struct
plat_serial8250_port to resource_size_t, which can be configured to be 64
bits on such platforms.  The mapbase in serial_struct can't safely be
changed, because that structure is user visible.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 8518fa2..afe0f6d 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -20,7 +20,7 @@
 struct plat_serial8250_port {
 	unsigned long	iobase;		/* io base address */
 	void __iomem	*membase;	/* ioremap cookie or NULL */
-	unsigned long	mapbase;	/* resource base */
+	resource_size_t	mapbase;	/* resource base */
 	unsigned int	irq;		/* interrupt number */
 	unsigned int	uartclk;	/* UART clock rate */
 	unsigned char	regshift;	/* register shift */