[POWERPC] Fix VDSO compile warning

Maybe the type should have been char[] instead of __u8[]
in the first place, but this will do.
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/vdso.c

@@ -670,7 +670,7 @@ static int __init vdso_init(void)
 	/*
 	 * Fill up the "systemcfg" stuff for backward compatiblity
 	 */
-	strcpy(vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
+	strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
 	vdso_data->version.major = SYSTEMCFG_MAJOR;
 	vdso_data->version.minor = SYSTEMCFG_MINOR;
 	vdso_data->processor = mfspr(SPRN_PVR);