m4: Remove unnecessary RIL flag

NEW_LIBRIL_HTC only matters if we're using libril from hardware/ril,
which we're not.

Change-Id: I177c85379d76f8f2a6ad08d0c94fe4aca4ab2c63
m4: Delete unused files

Change-Id: I12534b00e2e6af92264ec895b394da2da920517c