Kconfig: rename CONFIG_SPL_USB_GADGET_SUPPORT as CONFIG_SPL_USB_GADGET

The SPL option for USB gadget should be named after the option for u-boot
(CONFIG_USB_GADGET)

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/configs/imx6q_logic_defconfig b/configs/imx6q_logic_defconfig
index 036069a..46312a0 100644
--- a/configs/imx6q_logic_defconfig
+++ b/configs/imx6q_logic_defconfig
@@ -24,7 +24,7 @@
 CONFIG_SPL_NAND_SUPPORT=y
 CONFIG_SPL_OS_BOOT=y
 CONFIG_SPL_USB_HOST_SUPPORT=y
-CONFIG_SPL_USB_GADGET_SUPPORT=y
+CONFIG_SPL_USB_GADGET=y
 CONFIG_SPL_USB_SDP_SUPPORT=y
 CONFIG_SPL_WATCHDOG_SUPPORT=y
 CONFIG_SYS_PROMPT="i.MX6 Logic # "