Top level makefile is using vpp as the default platform. The other place
where platform is specified has native as the default. Unite them to the
only currently supported platform - vpp.
Type: make
Change-Id: Idb12ccc3056dd6be640a2d6763dc30e4f789d2ac
Signed-off-by: juraj.linkes <juraj.linkes@pantheon.tech>