dfu: Rename _FUNCTION_DFU to DFU_OVER_

Do the following to make the symbol names less confusing.

sed -i "s/\([TU][^_]\+\)_FUNCTION_DFU/DFU_OVER_\1/g" \
	`git grep _FUNCTION_DFU | cut -d ":" -f 1 | sort -u`

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Lukasz Majewski <lukma@denx.de>
diff --git a/drivers/dfu/Kconfig b/drivers/dfu/Kconfig
index b077444..51ab484 100644
--- a/drivers/dfu/Kconfig
+++ b/drivers/dfu/Kconfig
@@ -2,21 +2,21 @@
 
 config DFU
 	bool
-	imply USB_FUNCTION_DFU if USB_GADGET
+	imply DFU_OVER_USB if USB_GADGET
 
-config USB_FUNCTION_DFU
+config DFU_OVER_USB
 	bool
 	select HASH
 	depends on USB_GADGET
 
-config TFTP_FUNCTION_DFU
+config DFU_OVER_TFTP
 	bool
 	depends on NET
 
 if DFU
 config DFU_TFTP
 	bool "DFU via TFTP"
-	select TFTP_FUNCTION_DFU
+	select DFU_OVER_TFTP
 	help
 	  This option allows performing update of DFU-managed medium with data
 	  sent via TFTP boot.