opencv: backport commit to compile with ppc

During the testing of the meta-ros layer, I discovered that opencv
does not cross-compile for the ppc architecture. The error is
reported in the meta-ros issue tracker #355 [1]. To address this
error,  this commit applies a patch that is already provided upstream
in the opencv version 3.0.

[1] https://github.com/bmwcarit/meta-ros/issues/355



Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>