usb: musb-new: CONFIG_MUSB prefix replacement with CONFIG_USB_MUSB

USB-related options are usually prefixed with CONFIG_USB and platform-specific
adaptation for the MUSB controller already have a CONFIG_USB_MUSB prefix, so
this switches all MUSB-related options to a CONFIG_USB_MUSB prefix, for
consistency.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
diff --git a/board/ti/am335x/board.c b/board/ti/am335x/board.c
index 96245a3..1dc2ed0 100644
--- a/board/ti/am335x/board.c
+++ b/board/ti/am335x/board.c
@@ -569,7 +569,7 @@
 #if ((defined(CONFIG_SPL_ETH_SUPPORT) || defined(CONFIG_SPL_USBETH_SUPPORT)) \
 		&& defined(CONFIG_SPL_BUILD)) || \
 	((defined(CONFIG_DRIVER_TI_CPSW) || \
-	  defined(CONFIG_USB_ETHER) && defined(CONFIG_MUSB_GADGET)) && \
+	  defined(CONFIG_USB_ETHER) && defined(CONFIG_USB_MUSB_GADGET)) && \
 	 !defined(CONFIG_SPL_BUILD))
 int board_eth_init(bd_t *bis)
 {