Bluetooth: hci_sync: revert some mesh modifications

This reverts minor parts of the changes made in commit b338d917
("Bluetooth: Implement support for Mesh"). It looks like these changes
were only made for development purposes but shouldn't have been part of
the commit.

Fixes: b338d917 ("Bluetooth: Implement support for Mesh")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>