package/weston: fix patch

The newly iontroduced patch was created against weston's master branch,
but was not rebased correctly on top of the release we are using, hence
it does not apply because files have been moved since the release.

Fixes:
    http://autobuild.buildroot.org/results/5fb/5fbfd26d05a0ccaf4a70a100a7499cedea83ce6f/
    http://autobuild.buildroot.org/results/769/76976fbfc2162c2c671a52eafdad82df6d25a660/



Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>