Add functions to return wimax service/device objects

Added FindWimaxDevice and FindWimaxService that returns
the device object and service object respectively.

BUG=None
TEST=network_MobileSuspendResume should work devices with cellular and wimax modems.

Change-Id: Iba522abedd6856816993c9268c1c0c9aa147b04d
Reviewed-on: https://gerrit.chromium.org/gerrit/36832
Reviewed-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Stanley Wong <stanleyw@chromium.org>
Tested-by: Stanley Wong <stanleyw@chromium.org>
Commit-Ready: Stanley Wong <stanleyw@chromium.org>
1 file changed