Lockscreen Media controls: Fix mdpi layout issues

Before: http://i.imgur.com/56jXhXG.png
After: http://i.imgur.com/wQJV3M1.png

Signed-off-by: kyryljan-serhij <kirilyan.sergei@gmail.com>
Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: Ib3f23a8e2d7e545495d78fe3e6b5a5b8d0adfac9