Bluetooth: Add event mask page 2 setting support

For those controller that support the HCI_Set_Event_Mask_Page_2 command
we should include it in the init sequence. This patch implements sending
of the command and enables the events in it based on supported features
(currently only CSB is checked).

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

include/net/bluetooth/hci.h

@@ -823,6 +823,8 @@ struct hci_rp_read_inq_rsp_tx_power {
 	__s8     tx_power;
 } __packed;
 
+#define HCI_OP_SET_EVENT_MASK_PAGE_2	0x0c63
+
 #define HCI_OP_READ_FLOW_CONTROL_MODE	0x0c66
 struct hci_rp_read_flow_control_mode {
 	__u8     status;