pinctrl: at91: use own header

Copy the mach/at91_pio.h header locally and use it for pinctrl-at91.c. This
allows to remove the dependency on mach/at91_pio.h to be able to move at91 to
multiplatform.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index a20df9b..c017d90 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7161,7 +7161,7 @@
 M:	Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
-F:	drivers/pinctrl/pinctrl-at91.c
+F:	drivers/pinctrl/pinctrl-at91.*
 
 PIN CONTROLLER - RENESAS
 M:	Laurent Pinchart <laurent.pinchart@ideasonboard.com>