Some upcoming platforms like broxton etc have extended manifest
in firmware binary. This is not required to be downloaded to DSP.
So driver needs to strip this before downloading.

Add a utility function to check if a header exists, and remove it
in that case
Signed-off-by: Ramesh Babu <ramesh.babu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>