MIPS: Alchemy: DB1300: Add touch penirq support

wire up the WM9713 pendown irq support.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/7563/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>