gpio: stmpe: pass DT node to irqdomain

The irq domain was implemented but the device tree
node was not transmitted to irq_domain_add_simple().

Cc: stable@vger.kernel.org
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>