[ARM] 4559/1: pxa: make PXA_LAST_GPIO a run-time variable

This definition produces processor specific code in generic function
pxa_gpio_mode(), thus creating inconsistencies for support of pxa25x
and pxa27x in a single zImage.

As David Brownell suggests, make it a run-time variable and initialize
at run-time according to the number of GPIOs on the processor. For now
the initialization happens in pxa_init_irq_gpio(),  since there is
already a parameter for that, besides, this is and MUST be earlier
than any subsequent calls to pxa_gpio_mode().

Signed-off-by: eric miao <eric.y.miao@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/generic.h b/arch/arm/mach-pxa/generic.h
index 5b11741..25bd9bf 100644
--- a/arch/arm/mach-pxa/generic.h
+++ b/arch/arm/mach-pxa/generic.h
@@ -20,6 +20,7 @@
 extern void __init pxa_map_io(void);
 
 extern unsigned int get_clk_frequency_khz(int info);
+extern int pxa_last_gpio;
 
 #define SET_BANK(__nr,__start,__size) \
 	mi->bank[__nr].start = (__start), \