mesa: remove libxml2-native dependency

mesa: remove libxml2-native dependency

Native libxml2 is only needed for xmllint which in turn is only needed
when build-tests meson option is enabled, which defaults to disabled and
isn't enabled by the recipe.

We may need to revisit this if we add ptest support in mesa I assume.

Let's remove it from the DEPENDS for now.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>