software node: replace is_array with is_inline

We do not need a special flag to know if we are dealing with an
array, as we can get that data from ratio between element length and
the data size, but we do need a flag to know whether or not the data
is stored directly inside property_entry.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[ rjw: Subject & changelog, struct property_entry kerneldoc ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>