Disable no-vendor-variant VNDK for CFI modules

If CFI is enabled for a module, no-vendor-variant VNDK will fail
because CFI is not used for the vendor variant.

Bug: 148638729
Test: Remove libstagefright_bufferpool@2.0 from the whitelist. Build on
      crosshatch is successful. Build on a ARM32 device with
      TARGET_VNDK_USE_CORE_VARIANT set and check no-vendor-variant VNDK
      is still enabled for libstagefright_bufferpool@2.0.

Change-Id: Ib0a411d7ea769097186afa802751b0796527ec76