[dts] [PATCH] tests/TestSuite_pipeline.py: Modify the hard coded app parameter

[Tu, Lijuan]

> Modify the hard coded app parameter to call the platform interface
> 
> Signed-off-by: Yogesh Jangra <yogesh.jangra at intel.com>
> Tested-by: Venkata Suresh Kumar P <venkata.suresh.kumar.p at intel.com>

Applied with commit message changed