nimble/controller: add HCI Set Event Mask Page 2 to supported commands

This patch adds HCI Set Event Mask Page 2 to the list of supported
commands. This command is already implemented in the controller but
was not listed as supported.

nimble/controller/src/ble_ll_hci_supp_cmd.c

@@ -64,6 +64,10 @@ static const uint8_t octet_15 = OCTET(
 #endif
 );
 
+static const uint8_t octet_22 = OCTET(
+    BIT(2) /* HCI Set Event Mask Page 2 */
+);
+
 static const uint8_t octet_25 = OCTET(
     BIT(0) /* HCI LE Set Event Mask */
     BIT(1) /* HCI LE Read Buffer Size [v1] */
@@ -307,7 +311,7 @@ static const uint8_t g_ble_ll_hci_supp_cmds[64] = {
     0,
     0,
     0,
-    0,
+    octet_22,
     0,
     0,
     octet_25,