[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.c b/arch/arm/mach-pxa/generic.c
index 1c5413f..eed95eaf 100644
--- a/arch/arm/mach-pxa/generic.c
+++ b/arch/arm/mach-pxa/generic.c
@@ -71,6 +71,7 @@
 /*
  * Handy function to set GPIO alternate functions
  */
+int pxa_last_gpio;
 
 int pxa_gpio_mode(int gpio_mode)
 {
@@ -79,7 +80,7 @@
 	int fn = (gpio_mode & GPIO_MD_MASK_FN) >> 8;
 	int gafr;
 
-	if (gpio > PXA_LAST_GPIO)
+	if (gpio > pxa_last_gpio)
 		return -EINVAL;
 
 	local_irq_save(flags);