ANDROID: GKI: enable PM_GENERIC_DOMAINS by default

This is needed to support the QCOM clk drivers as modules without
building them in. We need to fix this properly upstream.

Signed-off-by: Will McVicker <willmcvicker@google.com>
Bug: 150638698
Bug: 147895101
Change-Id: I69b59455e4e2d8ef3a183ee52a835ddb97360420