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/configs/myir_mys_6ulx_defconfig b/configs/myir_mys_6ulx_defconfig
index 3ee7a78..d7a68d6 100644
--- a/configs/myir_mys_6ulx_defconfig
+++ b/configs/myir_mys_6ulx_defconfig
@@ -22,7 +22,7 @@
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL_DMA=y
 CONFIG_SPL_NAND_SUPPORT=y
-CONFIG_SPL_USB_HOST_SUPPORT=y
+CONFIG_SPL_USB_HOST=y
 CONFIG_SPL_USB_GADGET=y
 CONFIG_SPL_WATCHDOG=y
 CONFIG_CMD_MEMTEST=y