package/kmsxx: add patch to fix LTO support

The LTO support in the kmsxx package uses the host gcc-ar and gcc-ranlib
instead of the ones from the cross-toolchain. Add a patch that tries to
find the right one based on CMAKE_C_COMPILER.

Fixes:
http://autobuild.buildroot.net/results/16a/16a38a4277dd1152a5955d62cb92f85447791ef3

Possibly also fixes:
http://autobuild.buildroot.net/results/f3c/f3c48da3a9706cd366c0e0a96c3cd0ff959f2a78


(it fails later, possibly because an incompatible host ar)

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>