arm: ep93xx: Don't try to release not acquired GPIO lines

Fail path of ep93xx_keypad_acquire_gpio() tries to release
GPIO lines not acquired successfully before. Fix this.
Signed-off-by: NRafal Prylowski <prylowski@metasoft.pl>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NRyan Mallon <rmallon@gmail.com>

arch/arm/mach-ep93xx/core.c

@@ -734,7 +734,7 @@ int ep93xx_keypad_acquire_gpio(struct platform_device *pdev)
 fail_gpio_d:
 	gpio_free(EP93XX_GPIO_LINE_C(i));
 fail_gpio_c:
-	for ( ; i >= 0; --i) {
+	for (--i; i >= 0; --i) {
 		gpio_free(EP93XX_GPIO_LINE_C(i));
 		gpio_free(EP93XX_GPIO_LINE_D(i));
 	}