[HALX64] Do not claim to handle display reset if you don't. Fix bootvid display initialization in x64 as a result.

The HalpBiosDisplayReset() function is currently stub-plemented.
Returning FALSE will make bootvid take the route of fully
re-initializing the VGA display all by itself.

hal/halx86/amd64/x86bios.c

@@ -510,7 +510,9 @@ HalpBiosDisplayReset(VOID)
 
     /* Restore previous flags */
     __writeeflags(OldEflags);
-#endif
     return TRUE;
+#else
+    /* This x64 HAL does NOT currently handle display reset (TODO) */
+    return FALSE;
+#endif
 }
-