greybus: fix some hasty bugs

greybus: fix some hasty bugs

Fix some omissions found in the code.
    - initialize and use the host device connections list
    - rename the interface connections list (was "functions")
    - use the interface connections list
    - define a spinlock protecting the connections lists
    - declare gb_operation_submit() in "operation.h"

And the cport id map lock is per-host device, it's shared across all
host devices.  There's no need for one in struct greybus_host_device.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>