Revert "Bluetooth: hci_sync: fix double free in 'hci_discovery_filter_clear()'"

This reverts commit 16852ecc which is
commit 2935e556 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Icc166794f4e54bac8a9dc0f5bf64370d6e92a197
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>