This function is used by the AARCH64 code to filter a few
remaining lines in case the dimensions are not suitably
aligned; it is furthermore also used by checkasm to actually
test the AARCH64 code against. But it is normally not used
and this patch therefore moves it in bwdifdsp.h as a static
inline function so that it can be avoided if possible
or inlined where necessary.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>