Add const guarantees

This patch adds const qualifiers to parameter of some methods.
It adds no value right now, but will make conversion of btif to C++
much easier.

Change-Id: I380a63484230f92aedfd4ff5e1ee72f30307d9d9
diff --git a/stack/include/btm_api.h b/stack/include/btm_api.h
index b3232f4..a195432 100644
--- a/stack/include/btm_api.h
+++ b/stack/include/btm_api.h
@@ -2517,7 +2517,7 @@
 ** Returns          pointer to entry, or NULL if not found
 **
 *******************************************************************************/
-extern tBTM_INQ_INFO *BTM_InqDbRead (BD_ADDR p_bda);
+extern tBTM_INQ_INFO *BTM_InqDbRead (const BD_ADDR p_bda);
 
 
 /*******************************************************************************
@@ -2768,7 +2768,7 @@
 **                  BTM_BUSY if command is already in progress
 **
 *******************************************************************************/
-extern tBTM_STATUS BTM_ReadRSSI (BD_ADDR remote_bda, tBTM_CMPL_CB *p_cb);
+extern tBTM_STATUS BTM_ReadRSSI (const BD_ADDR remote_bda, tBTM_CMPL_CB *p_cb);
 
 
 /*******************************************************************************