package/sane-backends: fix gcc-4.8 compile

package/sane-backends: fix gcc-4.8 compile

Add patch to use legacy initializer variant to fix gcc-4.8 compile.

Fixes:

  - http://autobuild.buildroot.net/results/9d1cd0d0aa8c929c4b1b23b04075c331c1be80e0

  genesys/utilities.h:229:23: error: invalid initialization of non-const reference of type 'std::basic_ios<char>&' from an rvalue of type '<brace-enclosed initializer list>'
           stream_{stream}
                         ^
  genesys/image_pipeline.cpp:715:19: error: invalid initialization of non-const reference of type 'genesys::ImagePipelineNode&' from an rvalue of type '<brace-enclosed initializer list>'
       source_{source}
                     ^

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>