lrdp-v2: ramdump: Fix symbol_at

GdbMI.symbol_at returns a string, not a GdbSymbol object, so the extra
field traversal is unnecessary.

Change-Id: I85acd83657e4b6055bd1f7945da73dcf9d4839f1

linux-ramdump-parser-v2/ramdump.py

@@ -989,7 +989,7 @@ class RamDump():
 
     def symbol_at(self, addr):
         try:
-            return self.gdbmi.symbol_at(addr).symbol
+            return self.gdbmi.symbol_at(addr)
         except gdbmi.GdbMIException:
             pass