gpio/powerpc: Eliminate duplication of of_get_named_gpio_flags()

A large chunk of qe_pin_request() is unnecessarily cut-and-paste
directly from of_get_named_gpio_flags().  This patch cuts out the
duplicate code and replaces it with a call to of_get_gpio().

v2: fixed compile error due to missing gpio_to_chip()

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 8c86210..6b10bdc1 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -135,6 +135,7 @@
 
 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
 			unsigned offset);
+extern struct gpio_chip *gpio_to_chip(unsigned gpio);
 extern int __must_check gpiochip_reserve(int start, int ngpio);
 
 /* add/remove chips */