The flag GRALLOC_USAGE_PRIVATE_UNCACHED can be set in the
usage to allow it to be uncached. If not set, the buffer
will be cached by default.
CRs-fixed: 341196
(cherry picked from commit 6232816aadd311dbb57b714c7c0a4073d3ddc7f7)
Change-Id: Ic10677d105328702972dd69581b919c984d17fe9