drm/msm/dsi-staging: fix few validation checks in ulps

Fix few validations related to Ultra-Low Power State in phy.
Move target specific register checks to appropriate phy
version file.

Change-Id: Idb85434ab11c7975eb2505ba1acaaf2d71198542
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>