forkfd: sync with OpenDCDiag

Matches 0cd579d973/framework/forkfd/forkfd.c

Change-Id: Ibf4acec0f166495998f7fffd16d6deb90aa05668
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/3rdparty/forkfd/forkfd.c

@@ -107,7 +107,7 @@ static int disable_fork_fallback(void)
     /* if there's no system forkfd, we have to use the fallback */
     return system_has_forkfd();
 #else
-    return false;
+    return 0;
 #endif
 }