swscale: Allow the max filter size to be set at compile time

This can help "extreme" resizes, e.g with some 4k stuff.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
MAINTAINERS: Added Tim Nicholson's key fingerprint

Signed-off-by: Tim.Nicholson <tim.nicholson@bbc.co.uk>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/rv34: fix edge emu with uv stride <= 25

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>