at91: introduce commom AT91_BASE_SYS

On all at91 except rm9200 and x40 have the System Controller starts
at address 0xffffc000 and has a size of 16KiB.

On rm9200 it's start at 0xfffe4000 of 111KiB with non reserved data starting
at 0xfffff000

This patch removes the individual definitions of AT91_BASE_SYS and
replaces them with a common version at base 0xfffffc000 and size 16KiB
and map the same memory space

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>

arch/arm/mach-at91/board-sam9263ek.c

@@ -56,7 +56,7 @@
 static void __init ek_init_early(void)
 {
 	/* Initialize processor: 16.367 MHz crystal */
-	at91sam9263_initialize(16367660);
+	at91_initialize(16367660);
 
 	/* DBGU on ttyS0. (Rx & Tx only) */
 	at91_register_uart(0, 0, 0);
@@ -452,7 +452,7 @@ static void __init ek_board_init(void)
 MACHINE_START(AT91SAM9263EK, "Atmel AT91SAM9263-EK")
 	/* Maintainer: Atmel */
 	.timer		= &at91sam926x_timer,
-	.map_io		= at91sam9263_map_io,
+	.map_io		= at91_map_io,
 	.init_early	= ek_init_early,
 	.init_irq	= ek_init_irq,
 	.init_machine	= ek_board_init,