of: Add a helper to free property struct

[ Upstream commit 1c5e3d9b ]

Freeing a property struct is 3 kfree()'s which is duplicated in multiple
spots. Add a helper, __of_prop_free(), and replace all the open coded
cases in the DT code.

Reviewed-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240409-dt-cleanup-free-v2-1-5b419a4af38d@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>
Stable-dep-of: 80af3745 ("of: dynamic: Fix use after free in of_changeset_add_prop_helper()")
Signed-off-by: Sasha Levin <sashal@kernel.org>