Bluetooth: hci_sync: Fix hci_read_buffer_size_sync

hci_read_buffer_size_sync shall not use HCI_OP_LE_READ_BUFFER_SIZE_V2
sinze that is LE specific, instead it is hci_le_read_buffer_size_sync
version that shall use it.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216382
Fixes: 26afbd82

 ("Bluetooth: Add initial implementation of CIS connections")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>