package/mesa3d: remove old patch for uClibc

This patch is no longer necessary since Buildroot is using uClibc-ng
and the patch [1] as been merged upstream.
It's 2017 and uClibc toolchains have been rebuild with uClibc-ng.

Drop upstream patch and rename remaining one.

[1] https://cgit.openadk.org/cgi/cgit/uclibc-ng.git/commit/?id=6c4538905e65ceb203f59aaa9a61728e81c6bc0a



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>