gpio: Add custom driver for Axxia SoCs

Some of the Axxia SoCs have a different interrupt structure
than the standard PL061 driver. This commit adds a driver
based on the PL061 driver but with the Axxia interrupt structure.

Signed-off-by: John Jacques <john.jacques@intel.com>
Signed-off-by: Charlie Paul <charlie.paul@windriver.com>
Signed-off-by: Daniel Dragomir <daniel.dragomir@windriver.com>