arm: socfpga: Add qts-filter.sh script

Add script which loads the QTS-generated sources and headers and converts
them into sensible format which can be used with much more easy in mainline
U-Boot. The script also filters out macros which makes no sense anymore, so
they don't pollute namespace and waste space.

Signed-off-by: Marek Vasut <marex@denx.de>