ARM: pxa/am200epd: fix leak in am200_init_gpio_regs error path

If gpio_request fails when i > 0, gpios[0] is not freed in current
implementation.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-pxa/am200epd.c b/arch/arm/mach-pxa/am200epd.c
index 10964e3..4cb069f 100644
--- a/arch/arm/mach-pxa/am200epd.c
+++ b/arch/arm/mach-pxa/am200epd.c
@@ -128,8 +128,8 @@
 	return 0;
 
 err_req_gpio:
-	while (i > 0)
-		gpio_free(gpios[i--]);
+	while (--i >= 0)
+		gpio_free(gpios[i]);
 
 	return err;
 }