ARM: Fix memset on TLB flush and initialization

Instead of clearing the entire TLB on initialization and flush, the code was
clearing only one element.  This patch corrects the memsets in the init and
flush routines.

src/arch/arm/tlb.cc

@@ -75,7 +75,7 @@ TLB::TLB(const Params *p)
     , rangeMRU(1), miscRegValid(false)
 {
     table = new TlbEntry[size];
-    memset(table, 0, sizeof(TlbEntry[size]));
+    memset(table, 0, sizeof(TlbEntry) * size);
 
 #if FULL_SYSTEM
     tableWalker->setTlb(this);
@@ -192,7 +192,7 @@ TLB::flushAll()
        x++;
     }
 
-    memset(table, 0, sizeof(TlbEntry[size]));
+    memset(table, 0, sizeof(TlbEntry) * size);
 
     flushTlb++;
 }