device property: Avoid potential dereferences of invalid pointers

Since fwnode may hold ERR_PTR(-ENODEV) or it may be NULL,
the fwnode type checks is_of_node(), is_acpi_node() and is
is_pset_node() need to consider it. Using IS_ERR_OR_NULL()
to check it.

Fixes: 0d67e0fa

 (device property: fix for a case of use-after-free)
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>