hwc3: Free drmConnector object after taking backup am: b6c77a1da5

Original change: https://android-review.googlesource.com/c/device/generic/goldfish-opengl/+/3375924

Change-Id: I0ca66fa248f7aeec77a90bb341c31738cf1598ec
Signed-off-by: Automerger Merge Worker <[email protected]>