python3: silence DeprecationWarnings in python3-config
Our patched python3-config uses distutils, but that will emit a
DeprecationWarning when imported. This isn't useful when using the
output of python3-config to find include paths.
This isn't a huge problem typically as the warning goes to stderr, but
some build systems read both stdout and stderr.
Signed-off-by: Ross Burton <ross.burton@arm.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>