Revert "Temporary changed how ro.sf.lcd_density is set so it can build on phone_car."

This reverts commit 5bba103051dfdafc0d2cda15bc7b5eb121c062ed.

Bug: 160821620
Bug: 160823761

Test: compiled and built on bonito_car; should be the same for others
Change-Id: I8a1f3b4b28775241f92a3bfc916149489abab42a