[Blackfin] arch: Fix BUG gpio_direction_output API is not compatitable with GENERIC_GPIO API interface

signef-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/arch/blackfin/mach-bf537/boards/stamp.c b/arch/blackfin/mach-bf537/boards/stamp.c
index 3e0ad04..37759ac 100644
--- a/arch/blackfin/mach-bf537/boards/stamp.c
+++ b/arch/blackfin/mach-bf537/boards/stamp.c
@@ -250,12 +250,7 @@
 void sl811_port_power(struct device *dev, int is_on)
 {
 	gpio_request(CONFIG_USB_SL811_BFIN_GPIO_VBUS, "usb:SL811_VBUS");
-	gpio_direction_output(CONFIG_USB_SL811_BFIN_GPIO_VBUS);
-
-	if (is_on)
-		gpio_set_value(CONFIG_USB_SL811_BFIN_GPIO_VBUS, 1);
-	else
-		gpio_set_value(CONFIG_USB_SL811_BFIN_GPIO_VBUS, 0);
+	gpio_direction_output(CONFIG_USB_SL811_BFIN_GPIO_VBUS, is_on);
 }
 #endif