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/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index ccf56ac..d43fc65 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -224,7 +224,7 @@
 	 * G5 machines... So when something asks for bus 0 io base
 	 * (bus 0 is HT root), we return the AGP one instead.
 	 */
-	if (in_bus == 0 && machine_is_compatible("MacRISC4")) {
+	if (in_bus == 0 && of_machine_is_compatible("MacRISC4")) {
 		struct device_node *agp;
 
 		agp = of_find_compatible_node(NULL, NULL, "u3-agp");