staging: unisys: moved visor_check_channel from include/channel.h to visorbus/visorbus_main.c

Moved the function visor_check_channel() from include/channel.h to
visorbus/visorbus_main.c.

Signed-off-by: Sameer Wadgaonkar <sameer.wadgaonkar@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: David Binder <david.binder@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>