libtraceevent: Move plugins into package of its own

From Peter Bergin <peter@berginkonsult.se>
see https://github.com/openembedded/meta-openembedded/pull/632/commits/cf672ba52f8c4d983ad9a74b67f226ac753a50f8

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-kernel/libtraceevent/libtraceevent_1.7.0.bb

@@ -20,4 +20,6 @@ do_install() {
     oe_runmake install DESTDIR=${D} pkgconfig_dir=${libdir}/pkgconfig
 }
 
-FILES:${PN} += "${libdir}/traceevent"
+PACKAGES += "${PN}-plugins"
+
+FILES:${PN}-plugins += "${libdir}/traceevent/plugins"