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/sound/ppc/burgundy.c b/sound/ppc/burgundy.c
index 0accfe4..1f72e1c 100644
--- a/sound/ppc/burgundy.c
+++ b/sound/ppc/burgundy.c
@@ -582,7 +582,7 @@
 static void snd_pmac_burgundy_update_automute(struct snd_pmac *chip, int do_notify)
 {
 	if (chip->auto_mute) {
-		int imac = machine_is_compatible("iMac");
+		int imac = of_machine_is_compatible("iMac");
 		int reg, oreg;
 		reg = oreg = snd_pmac_burgundy_rcb(chip,
 				MASK_ADDR_BURGUNDY_MORE_OUTPUTENABLES);
@@ -620,7 +620,7 @@
  */
 int __devinit snd_pmac_burgundy_init(struct snd_pmac *chip)
 {
-	int imac = machine_is_compatible("iMac");
+	int imac = of_machine_is_compatible("iMac");
 	int i, err;
 
 	/* Checks to see the chip is alive and kicking */