ARM: GIC: consolidate gic_cpu_base_addr to common GIC code

Every architecture using the GIC has a gic_cpu_base_addr pointer for
GIC 0 for their entry assembly code to use to decode the cause of the
current interrupt.  Move this into the common GIC code.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/hardware/gic.h

@@ -33,6 +33,8 @@
 #define GIC_DIST_SOFTINT		0xf00
 
 #ifndef __ASSEMBLY__
+extern void __iomem *gic_cpu_base_addr;
+
 void gic_init(unsigned int, unsigned int, void __iomem *, void __iomem *);
 void gic_secondary_init(unsigned int);
 void gic_cascade_irq(unsigned int gic_nr, unsigned int irq);