tinyalsa: fix build with gcc 5.x

This commit adds a patch to tinyalsa to fix the build with gcc 5.x. It
fixes autobuilder issues like:

  http://autobuild.buildroot.net/results/d19/d19d1779da473d7adee2a18fea990fa19c7a7697/



The fix has been submitted upstream.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>