[ARM] pxa: allow dynamic enable/disable of GPIO wakeup for pxa{25x,27x}

Changes include:

1. rename MFP_LPM_WAKEUP_ENABLE into MFP_LPM_CAN_WAKEUP to indicate
   the board capability of this pin to wakeup the system

2. add gpio_set_wake() and keypad_set_wake() to allow dynamically
   enable/disable wakeup from GPIOs and keypad GPIO

   * these functions are currently kept in mfp-pxa2xx.c due to their
     dependency to the MFP configuration

3. pxa2xx_mfp_config() only gives early warning if MFP_LPM_CAN_WAKEUP
   is set on incorrect pins

So that the GPIO's wakeup capability is now decided by the following:

   a) processor's capability: (only those GPIOs which have dedicated
      bits within PWER/PRER/PFER can wakeup the system), this is
      initialized by pxa{25x,27x}_init_mfp()

   b) board design decides:
      - whether the pin is designed to wakeup the system (some of
        the GPIOs are configured as other functions, which is not
        intended to be a wakeup source), by OR'ing the pin config
        with MFP_LPM_CAN_WAKEUP

      - which edge the pin is designed to wakeup the system, this
        may depends on external peripherals/connections, which is
        totally board specific; this is indicated by MFP_LPM_EDGE_*

   c) the corresponding device's (most likely the gpio_keys.c) wakeup
      attribute:

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/pxa25x.c b/arch/arm/mach-pxa/pxa25x.c
index 653a3b6..c486c30 100644
--- a/arch/arm/mach-pxa/pxa25x.c
+++ b/arch/arm/mach-pxa/pxa25x.c
@@ -26,6 +26,7 @@
 #include <asm/hardware.h>
 #include <asm/arch/irqs.h>
 #include <asm/arch/pxa-regs.h>
+#include <asm/arch/mfp-pxa25x.h>
 #include <asm/arch/pm.h>
 #include <asm/arch/dma.h>
 
@@ -230,24 +231,10 @@
 static int pxa25x_set_wake(unsigned int irq, unsigned int on)
 {
 	int gpio = IRQ_TO_GPIO(irq);
-	uint32_t gpio_bit, mask = 0;
+	uint32_t mask = 0;
 
-	if (gpio >= 0 && gpio <= 15) {
-		gpio_bit = GPIO_bit(gpio);
-		mask = gpio_bit;
-		if (on) {
-			if (GRER(gpio) | gpio_bit)
-				PRER |= gpio_bit;
-			else
-				PRER &= ~gpio_bit;
-
-			if (GFER(gpio) | gpio_bit)
-				PFER |= gpio_bit;
-			else
-				PFER &= ~gpio_bit;
-		}
-		goto set_pwer;
-	}
+	if (gpio >= 0 && gpio < 85)
+		return gpio_set_wake(gpio, on);
 
 	if (irq == IRQ_RTCAlrm) {
 		mask = PWER_RTC;