Revert "msm: Display Control: change the default sysfs path for something more readable."

Reverted by the original author request. Explanation: "My proposal for a final path would be something like /sys/modules/mdss_dsi/* but please, both of you give me a day or two to look into other stuff before deciding on this (unimportant) matter."

This reverts commit 163a1d6dc4ef40e339b173522d76970ebe1a6b1e.