ppc4xx: Correct GPIO offset in gpio_config()

Thanks to Gary Jennejohn for pointing this out.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/cpu/ppc4xx/gpio.c b/cpu/ppc4xx/gpio.c
index dcf1fba..7b09a2f 100644
--- a/cpu/ppc4xx/gpio.c
+++ b/cpu/ppc4xx/gpio.c
@@ -47,7 +47,7 @@
 	}
 
 	if (pin >= GPIO_MAX/2) {
-		offs2 = 0x100;
+		offs2 = 0x4;
 		pin2 = (pin - GPIO_MAX/2) << 1;
 	}