Return 0 on success for the mount() and unmount() compatibility calls. Just cleaner.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39362 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/libroot/os/arch/x86/compatibility.c

@@ -125,7 +125,7 @@ mount(const char *filesystem, const char *where, const char *device, ulong flags
 		errno = err;
 		return -1;
 	}
-	return err;
+	return 0;
 }
 
 
@@ -139,6 +139,6 @@ unmount(const char *path)
 		errno = err;
 		return -1;
 	}
-	return err;
+	return 0;
 }