gpio/langwell: convert to use irq_domain

irq_domain already provides a facility to translate from hardware IRQ
numbers to Linux IRQ numbers so use that instead of open-coding the logic
in the driver.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 7875c3f..8ee6d29 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -404,6 +404,7 @@
 config GPIO_LANGWELL
 	bool "Intel Langwell/Penwell GPIO support"
 	depends on PCI && X86
+	select IRQ_DOMAIN
 	help
 	  Say Y here to support Intel Langwell/Penwell GPIO.