microblaze: Fix sparse warning - cpuinfo.h

Warning log:
CHECK   arch/microblaze/kernel/cpu/cpuinfo-static.c
arch/microblaze/include/asm/cpuinfo.h:101:21: warning: incorrect type in argument 1 (different signedness)
arch/microblaze/include/asm/cpuinfo.h:101:21:    expected unsigned int const [usertype] *p
arch/microblaze/include/asm/cpuinfo.h:101:21:    got int *[assigned] val
...
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/cpuinfo.h

@@ -96,8 +96,8 @@ void set_cpuinfo_pvr_full(struct cpuinfo *ci, struct device_node *cpu);
 
 static inline unsigned int fcpu(struct device_node *cpu, char *n)
 {
-	int *val;
-	return (val = (int *) of_get_property(cpu, n, NULL)) ?
+	const __be32 *val;
+	return (val = of_get_property(cpu, n, NULL)) ?
 							be32_to_cpup(val) : 0;
 }