mm/Kconfig: Relax CMA optimization dependencies

The CMA performance optimizations depend on QGKI, which
prevents them from being enabled on configurations that don't
have a notion of GKI and QGKI. Thus, remove this dependency.
This shouldn't cause any problems with the ABI surface with
respect to GKI targets as the configs still have to be enabled
explicitly anyway.

Change-Id: I1bea32ccf23e485f491dfb27422f83d0919aedd6
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>