pinctrl: aspeed: Fix missed include

Some SPDX churn made my fixes drop an important include
from the Aspeed pinctrl header. Fix it up.

Cc: Andrew Jeffery <andrew@aj.id.au>
Reported-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/pinctrl-aspeed.h

@@ -16,6 +16,8 @@
 #include <linux/pinctrl/pinconf-generic.h>
 #include <linux/regmap.h>
 
+#include "pinmux-aspeed.h"
+
 /*
  * The ASPEED SoCs provide typically more than 200 pins for GPIO and other
  * functions. The SoC function enabled on a pin is determined on a priority