ARM: shmobile: fix smp build

I got build errors with the new version now because machine_is_kzm9g is no longer
defined:

arch/arm/mach-shmobile/platsmp.c: In function 'shmobile_smp_get_core_count':
arch/arm/mach-shmobile/platsmp.c:29:2: error: implicit declaration of function 'of_machine_is_compatible'

Replace the missing function with a call to of_machine_is_compatible.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Magnus Damm <magnus.damm@gmail.com>

arch/arm/boot/dts/sh73a0-kzm9g.dts

@@ -13,7 +13,7 @@
 
 / {
 	model = "KZM-A9-GT";
-	compatible = "renesas,kzm9g";
+	compatible = "renesas,kzm9g", "renesas,sh73a0";
 
 	memory {
 		device_type = "memory";

arch/arm/mach-shmobile/platsmp.c

@@ -16,11 +16,13 @@
 #include <linux/device.h>
 #include <linux/smp.h>
 #include <linux/io.h>
+#include <linux/of.h>
 #include <asm/hardware/gic.h>
 #include <asm/mach-types.h>
 #include <mach/common.h>
 
-#define is_sh73a0() (machine_is_ag5evm() || machine_is_kota2() || machine_is_kzm9g())
+#define is_sh73a0() (machine_is_ag5evm() || machine_is_kota2() || \
+			of_machine_is_compatible("renesas,sh73a0"))
 #define is_r8a7779() machine_is_marzen()
 
 static unsigned int __init shmobile_smp_get_core_count(void)