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/windfarm_smu_sensors.c b/drivers/macintosh/windfarm_smu_sensors.c
index 9c567b9..3c19350 100644
--- a/drivers/macintosh/windfarm_smu_sensors.c
+++ b/drivers/macintosh/windfarm_smu_sensors.c
@@ -363,9 +363,9 @@
 	 * I yet have to figure out what's up with 8,2 and will have to
 	 * adjust for later, unless we can 100% trust the SDB partition...
 	 */
-	if ((machine_is_compatible("PowerMac8,1") ||
-	     machine_is_compatible("PowerMac8,2") ||
-	     machine_is_compatible("PowerMac9,1")) &&
+	if ((of_machine_is_compatible("PowerMac8,1") ||
+	     of_machine_is_compatible("PowerMac8,2") ||
+	     of_machine_is_compatible("PowerMac9,1")) &&
 	    cpuvcp_version >= 2) {
 		pow->quadratic = 1;
 		DBG("windfarm: CPU Power using quadratic transform\n");