isl_point.c: add missing copyright statement
isl_point.c: add missing copyright statement

Signed-off-by: Sven Verdoolaege <dd860110a62b19214c4ee03aec0abffecb4e86b8@cerebras.net>

Meinersbur/isl,Meinersbur/isl,Meinersbur/isl,Meinersbur/isl