warnings: fix missing field in initializer

use generic struct zero initializer instead.
Older gcc used on arm also seem to have trouble with '{}',
so use '{ 0 }' instead

Change-Id: I83d43b05f8d1d44e1dd86502b48e28fe242e1db2

arch/arm64/kernel/cputable.c

@@ -10,5 +10,5 @@ struct cpu_info cpu_table[] = {
 		.cpu_name	= "AArch64 Processor",
 		.cpu_setup	= __cpu_setup,
 	},
-	{ /* Empty */ },
+	{ 0 },
 };