Rename SPL_USB_HOST_SUPPORT to SPL_USB_HOST

Rename this option so that CONFIG_IS_ENABLED can be used with it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-imx/mx6/Kconfig b/arch/arm/mach-imx/mx6/Kconfig
index d460268..d5664a1 100644
--- a/arch/arm/mach-imx/mx6/Kconfig
+++ b/arch/arm/mach-imx/mx6/Kconfig
@@ -312,7 +312,7 @@
 	select SPL_SEPARATE_BSS if SPL
 	select SPL_SERIAL_SUPPORT if SPL
 	select SPL_USB_GADGET if SPL
-	select SPL_USB_HOST_SUPPORT if SPL
+	select SPL_USB_HOST if SPL
 	select SPL_USB_SDP_SUPPORT if SPL
 	select SPL_WATCHDOG if SPL
 	select SUPPORT_SPL