hwc: fix for not ignoring framebuffer

If the FB is not used, because all the app layers are overlays, then set the
flag to have the driver not fetch from the FB pipe.

Bug: 7183992
Change-Id: I96ecc1610ac052e8512158d189b0614ecf82d139
Signed-off-by: Iliyan Malchev <malchev@google.com>
3 files changed