Revert "drm/msm/sde: sde encoder virtualization"

This reverts 'commit a142ec80 ("drm/msm/sde: sde
encoder virtualization")'
This is partial change for display drm driver,
that will break drm/sde merge commit.

Change-Id: Ida1e127788961e1c9484b0a69695d0ad5391cf88
Signed-off-by: Narendra Muppalla <NarendraM@codeaurora.org>