Force regenerating the header via i4_gen_header instead of i4_header_mode

If i4_header_mode is set (without the caller explicitly requesting it),
the next frame to be encoded will be missed altogether (when only
a header is output).

Instead force a header to be generated prepended to the next frame.
If the caller explicitly requests header mode, it will be output
in a separate call.

Change-Id: If475717edf980bccb2076f880c60c9dd7dede904
2 files changed