FM: Add SSR support for cherokee

This provide hardware error event to FM module during SOC
failure and resets FM gracefully.

Change-Id: Ic4345e02c8a1cba218414afdfcf3e76734c314b0
diff --git a/helium/radio-helium.h b/helium/radio-helium.h
index 9952884..8599316 100644
--- a/helium/radio-helium.h
+++ b/helium/radio-helium.h
@@ -497,6 +497,8 @@
 #define HCI_EV_SEARCH_LIST_COMPLETE     0x14
 #define HCI_EV_RADIO_TEXT_PLUS_ID       0x18
 #define HCI_EV_RADIO_TEXT_PLUS_TAG      0x19
+#define HCI_EV_HW_ERR_EVENT             0x1A
+
 
 #define HCI_REQ_DONE      0
 #define HCI_REQ_PEND      1