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>