SF: Temporarily expose primary display id

WM needs to know the address of the primary display in order to
consume ro.surface_flinger.primary_display_orientation correctly.
This path will be removed in the future once we support per
display install orientations.

Bug: 196167822
Test: check initial buffer transforms on displays with a different
install orientation

Merged-In: I2b0a92196a8a1f05f7d99b531775b9979f07af98
Change-Id: I2b0a92196a8a1f05f7d99b531775b9979f07af98