Use different hwcomposer HALs for hikey and hikey960

Instead of conditionally compiling hwcomposer.drm for hikey and
hikey960, compile two different modules and selectively use them
on hikey and hikey960.

Bug: 122332597
Test: none
Change-Id: Ifcb64798bc34101d9e1f851454c3fe361c478c12
6 files changed