powerpc: Fix early boot accounting of CPUs

smp_release_cpus() waits for all cpus (including the bootcpu) due to an
off-by-one count on boot_cpu_count (which is all CPUs).  This patch replaces
that with spinning_secondaries (which is all secondary CPUs).

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/prom.c

@@ -69,6 +69,7 @@ unsigned long tce_alloc_start, tce_alloc_end;
 u64 ppc64_rma_size;
 #endif
 static phys_addr_t first_memblock_size;
+static int __initdata boot_cpu_count;
 
 static int __init early_parse_mem(char *p)
 {
@@ -748,6 +749,13 @@ void __init early_init_devtree(void *params)
 	 */
 	of_scan_flat_dt(early_init_dt_scan_cpus, NULL);
 
+#if defined(CONFIG_SMP) && defined(CONFIG_PPC64)
+	/* We'll later wait for secondaries to check in; there are
+	 * NCPUS-1 non-boot CPUs  :-)
+	 */
+	spinning_secondaries = boot_cpu_count - 1;
+#endif
+
 	DBG(" <- early_init_devtree()\n");
 }