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/video/aty/aty128fb.c b/drivers/video/aty/aty128fb.c
index e4e4d43..9ee67d6 100644
--- a/drivers/video/aty/aty128fb.c
+++ b/drivers/video/aty/aty128fb.c
@@ -1931,22 +1931,22 @@
 			 * PowerMac2,2 summer 2000 iMacs
 			 * PowerMac4,1 january 2001 iMacs "flower power"
 			 */
-			if (machine_is_compatible("PowerMac2,1") ||
-			    machine_is_compatible("PowerMac2,2") ||
-			    machine_is_compatible("PowerMac4,1"))
+			if (of_machine_is_compatible("PowerMac2,1") ||
+			    of_machine_is_compatible("PowerMac2,2") ||
+			    of_machine_is_compatible("PowerMac4,1"))
 				default_vmode = VMODE_1024_768_75;
 
 			/* iBook SE */
-			if (machine_is_compatible("PowerBook2,2"))
+			if (of_machine_is_compatible("PowerBook2,2"))
 				default_vmode = VMODE_800_600_60;
 
 			/* PowerBook Firewire (Pismo), iBook Dual USB */
-			if (machine_is_compatible("PowerBook3,1") ||
-			    machine_is_compatible("PowerBook4,1"))
+			if (of_machine_is_compatible("PowerBook3,1") ||
+			    of_machine_is_compatible("PowerBook4,1"))
 				default_vmode = VMODE_1024_768_60;
 
 			/* PowerBook Titanium */
-			if (machine_is_compatible("PowerBook3,2"))
+			if (of_machine_is_compatible("PowerBook3,2"))
 				default_vmode = VMODE_1152_768_60;
 	
 			if (default_cmode > 16)