[OE-core] gtk+3: Add missing MLPREFIX

[Richard Purdie]

Without this each tries to provide libgtk-3.0 which directly conflict when
using multilibs.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>

diff --git a/meta/recipes-gnome/gtk+/gtk+3.inc b/meta/recipes-gnome/gtk+/gtk+3.inc
index 54ca77a..3e36676 100644
--- a/meta/recipes-gnome/gtk+/gtk+3.inc
+++ b/meta/recipes-gnome/gtk+/gtk+3.inc
@@ -105,6 +105,6 @@ python populate_packages_prepend () {
     do_split_packages(d, printmodules_root, '^libprintbackend-(.*)\.so$', 'gtk3-printbackend-%s', 'GTK printbackend module for %s')
 
     if (d.getVar('DEBIAN_NAMES', 1)):
-        d.setVar('PKG_${PN}', 'libgtk-3.0')
+        d.setVar('PKG_${PN}', '${MLPREFIX}libgtk-3.0')
 }