ARM: set vga memory base at run-time

Convert the incorrectly named PCIMEM_BASE to a variable called vga_base.
This removes the dependency on mach/hardware.h.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mm/iomap.c

@@ -9,6 +9,9 @@
 #include <linux/ioport.h>
 #include <linux/io.h>
 
+unsigned long vga_base;
+EXPORT_SYMBOL(vga_base);
+
 #ifdef __io
 void __iomem *ioport_map(unsigned long port, unsigned int nr)
 {