staging: vt6656: vnt_set_channel remove power setting functions

Power setting is already done in vnt_config and vnt_tx_packet.

Just check that for connection_channel, if invalid return.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>