Bluetooth: Remove unnecessary NULL check in hci_inquiry_cache_update

The ssp parameter is supposed to be a mandatory one and there are no
callers that would pass NULL to this function. Removing this unnecessary
NULL check also makes (false positive) static analyzer warnings go away.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>