Bluetooth: hci_sync: Fix not setting mask for HCI_EVT_LE_ALL_REMOTE_FEATURES_COMPLETE

Bluetooth: hci_sync: Fix not setting mask for HCI_EVT_LE_ALL_REMOTE_FEATURES_COMPLETE

This fixes not setting the bit for HCI_EVT_LE_ALL_REMOTE_FEATURES_COMPLETE
when extended features bit is set otherwise the controller may not
generate HCI_EVT_LE_ALL_REMOTE_FEATURES_COMPLETE causing
hci_le_read_all_remote_features_sync to timeout waiting for it.

Also remove dead code.

Fixes: a106e50be74b ("Bluetooth: HCI: Add support for LL Extended Feature Set")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>