ARM: pxa: define palmte2_pxa_keys conditionally

Gcc prints a harmless warning about palmte2_pxa_keys not being used
when the gpio keyboard driver is disabled. The solution is to use
the same #ifdef that is already present in the place where the
symbol is used.

Without this patch, building palmz72_defconfig results in:

/home/arnd/linux-arm/arch/arm/mach-pxa/palmte2.c:128:31: warning: 'palmte2_pxa_keys' defined but not used [-Wunused-variable]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Carlos Eduardo Medaglia Dyonisio <cadu@nerdfeliz.com>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Eric Miao <eric.y.miao@gmail.com>

arch/arm/mach-pxa/palmte2.c

@@ -105,6 +105,7 @@ static struct pxamci_platform_data palmte2_mci_platform_data = {
 	.gpio_power		= GPIO_NR_PALMTE2_SD_POWER,
 };
 
+#if defined(CONFIG_KEYBOARD_GPIO) || defined(CONFIG_KEYBOARD_GPIO_MODULE)
 /******************************************************************************
  * GPIO keys
  ******************************************************************************/
@@ -132,6 +133,7 @@ static struct platform_device palmte2_pxa_keys = {
 		.platform_data = &palmte2_pxa_keys_data,
 	},
 };
+#endif
 
 /******************************************************************************
  * Backlight