[EFL] Add eldbus to the library list
https://bugs.webkit.org/show_bug.cgi?id=139120

Reviewed by Gyuyoung Kim.

Fix undefined reference errors for eldbus APIs.

* PlatformEfl.cmake:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@176590 268f45cc-cd09-0410-ab3c-d52691b4dbfc