Revert "Add PRODUCT_BOOTANIMATION"

Replace this with TARGET_BOOTANIMATION as part of the
rework of the boot animation generation process in
vendor/cm change Iee32f18440ff955d13ed85b273e97cbd540721fc.

This reverts commit b2483ae0.

Change-Id: Id6fc55ee1bc0149f25e6165a3e5f3209ad4424fc
(cherry picked from commit 74b51197)