jsm: Removing unused jsm_channel->ch_wopen field

Currently the jsm_channel->ch_wopen field is defined and never
used. So, this patch removes it.

Signed-off-by: Breno Leitão <leitao@linux.vnet.ibm.com>
Cc: Scott Kilau <Scott.Kilau@digi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>