of: add 'of_' prefix to machine_is_compatible()

machine is compatible is an OF-specific call.  It should have
the of_ prefix to protect the global namespace.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Michal Simek <monstr@monstr.eu>
diff --git a/drivers/macintosh/adb.c b/drivers/macintosh/adb.c
index 23741ce..d840a10 100644
--- a/drivers/macintosh/adb.c
+++ b/drivers/macintosh/adb.c
@@ -322,8 +322,8 @@
 		adb_controller = NULL;
 	} else {
 #ifdef CONFIG_PPC
-		if (machine_is_compatible("AAPL,PowerBook1998") ||
-			machine_is_compatible("PowerBook1,1"))
+		if (of_machine_is_compatible("AAPL,PowerBook1998") ||
+			of_machine_is_compatible("PowerBook1,1"))
 			sleepy_trackpad = 1;
 #endif /* CONFIG_PPC */