LSB 4.1 Library Check: fix unable to find library libqt-mt.so.3

LSB 4.1 Library Check: fix unable to find library libqt-mt.so.3

The libqt-mt is tested by lsb-dist-checker and lsb-test-desktop,
and it locates in meta-qt3 layer.
So if meta-qt3 is not added, there should be a warning to call
attention; if added, it will add libqt-mt to RDEPENDS.

[YOCTO #5153]

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>