vts: fix some tunerhal vts fail without frontend device

PD#OTT-27646
bug:222020221

Problem:
some tunerhal vts fail without frontend device

Solution:
fix some logic errors without frontend device

verify:
ohm

Change-Id: I611a81400eb21bb52d59281f2266f3a95e015de9
Signed-off-by: junchao yuan <junchao.yuan@amlogic.com>
1 file changed