gpio: gpio-pl061: Use %pa to print 'resource_size_t'

The following build warning is generated when building multi_v7_defconfig with
LPAE option selected:

drivers/gpio/gpio-pl061.c:358:2: warning: format '%x' expects argument of type 'unsigned int', but argument 3 has type 'resource_size_t' [-Wformat=]

Fix it by using %pa to print 'resource_size_t'.

Reported-by: Olof's autobuilder <build@lixom.net>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>