cleanup: removed unused -m option

-m was introduced to support "direct import" without searching them in
import dirs (-I), which was the case of compiling API dump.

But now we use -I (import dirs) -p (imported preprocessed modules), but
do not use -m any longer.

Bug: n/a
Test: m
Change-Id: I3943e4d992213fdaa48693bd2539d544019fa802
3 files changed