Drivers: gpio: Fix spelling errors

Fixed several spelling errors in gpio-lynxpoint, gpio-pca953x,
gpio-tegra, gpio-zynq, gpiolib-of, gpiolib.

Signed-off-by: Colin Cronin <colinpatrickcronin@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index a6c67c6..9a0ec48 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -242,7 +242,7 @@
 {
 	/*
 	 * We're discouraging gpio_cells < 2, since that way you'll have to
-	 * write your own xlate function (that will have to retrive the GPIO
+	 * write your own xlate function (that will have to retrieve the GPIO
 	 * number and the flags from a single gpio cell -- this is possible,
 	 * but not recommended).
 	 */