ANDROID: GKI: arm64: gki_defconfig: Enable REGULATOR_PROXY_CONSUMER

This needs to be enabled for regulator driver modules to work. So,
enable it.

Bug: 155357256
Signed-off-by: Saravana Kannan <saravanak@google.com>
Change-Id: I1ba50d89973667783e61732319a4e155dcc42b41
Signed-off-by: Will McVicker <willmcvicker@google.com>