msm_fb: display: Free staged foreground pipes during suspend

During suspend, some foreground pipes might still be staged and
have to be removed before disabling timing generator.
So, these pipes are staged down and freed before timing generator
is switched off.

Change-Id: I3f2376cac43464c64cd1c9e2f16f3d801298c25d
Signed-off-by: Ravishangar Kalyanam <rkalya@codeaurora.org>

Conflicts:

	drivers/video/msm/mdp4_overlay.c