powerpc/powernv: Get cpu only after validity check

Check for validity of cpu before calling get_hard_smp_processor_id().

Found with coverity.
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/smp.c

@@ -57,7 +57,7 @@ static void pnv_smp_setup_cpu(int cpu)
 
 static int pnv_smp_kick_cpu(int nr)
 {
-	unsigned int pcpu = get_hard_smp_processor_id(nr);
+	unsigned int pcpu;
 	unsigned long start_here =
 			__pa(ppc_function_entry(generic_secondary_smp_init));
 	long rc;
@@ -66,6 +66,7 @@ static int pnv_smp_kick_cpu(int nr)
 	if (nr < 0 || nr >= nr_cpu_ids)
 		return -EINVAL;
 
+	pcpu = get_hard_smp_processor_id(nr);
 	/*
 	 * If we already started or OPAL is not supported, we just
 	 * kick the CPU via the PACA