staging: most: remove always true comparison

channel->dev has already been checked for NULL and if it was NULL then
we have returned with -EPIPE. So at this point it can not be NULL.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>