Bluetooth: Remove unnecessary params variable from process_adv_report()

The params variable was just used for storing the return value from the
hci_pend_le_action_lookup() function and then checking whether it's NULL
or not. We can simplify the code by checking the return value directly.

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