sigProcLib: Constify demodulation functions burst argument.

demodCommon() used to scale input vector in place which changed original data.
That's a bad practice and is not really necessary, so I've changed the code to
scale burst after it's copied to a new vector during a delay operation.

Change-Id: Ic45f71b634e48808356d68925bb9f5783e0bf0d3
2 files changed