thunderbolt: property: Fix a missing check of kzalloc

[ Upstream commit 6183d5a51866f3acdeeb66b75e87d44025b01a55 ]

No check is enforced for the return value of kzalloc,
which may lead to NULL-pointer dereference.

The patch fixes this issue.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>