selftest/vDSO: fix O=

selftest/vDSO: fix O=

BugLink: http://bugs.launchpad.net/bugs/1786352
[ Upstream commit 70b574e7d719bdf96d26528cb289f3e782e83979 ]

The vDSO selftests ignored the O= or KBUILD_OUTPUT= parameters. Fix it.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>