staging: vt6656: rxtx.c s_vGenerateTxParameter Create vnt_mic_hdr structure

Create double pointer to pass back vnt_mic_hdr address position
of relevant structure if need_mic is more than 0. Otherwise it
is NULL.

This replaces the pMICHDR void pointer with struct vnt_mic_hdr
and assignments in the calling functions.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>