Stamp out some x86/host mode warnings

Nuked a void* cast warnings and moved cacheflush into a target-specific
utility wrapper.

Change-Id: I36c841288b9ec7e03c0cb29b2e89db344f36fad1
diff --git a/vm/compiler/codegen/x86/ArchUtility.c b/vm/compiler/codegen/x86/ArchUtility.c
index 171c3b5..f7c48d6 100644
--- a/vm/compiler/codegen/x86/ArchUtility.c
+++ b/vm/compiler/codegen/x86/ArchUtility.c
@@ -22,3 +22,9 @@
 void dvmCompilerCodegenDump(CompilationUnit *cUnit)
 {
 }
+
+/* Target-specific cache flushing (not needed for x86 */
+int dvmCompilerCacheFlush(long start, long end, long flags)
+{
+    return 0;
+}