lttng2-ust: Backport patch from oe-core to fix parallel build issue

* taken from http://git.openembedded.org/openembedded-core/commit/?id=b947dbc72b3cd03901112c1bab6ac0b81f1b374f

[GF-2894] lttng-ust: Patch Makefile to fix build failure

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@palm.com>

Change-Id: I7804f30cd29e4d1a9876877d710b7001f353c608
Reviewed-on: https://g2g.palm.com/1794
Reviewed-by: Susan Montooth <susan.montooth@lge.com>
Tested-by: Susan Montooth <susan.montooth@lge.com>
Reviewed-by: Build Verification