Blackfin: fix SMP build error in start_thread()

Commit d5ce528c8e46fa5afb9 (Blackfin: convert irq/process to asm-generic)
incorrectly merged the smp and non-smp cases of start_thread() causing the
L1 stack to be setup on the SMP port instead of the UP port.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c
index 430ae39..5cc7e2e 100644
--- a/arch/blackfin/kernel/process.c
+++ b/arch/blackfin/kernel/process.c
@@ -151,7 +151,7 @@
 	regs->pc = new_ip;
 	if (current->mm)
 		regs->p5 = current->mm->start_data;
-#ifdef CONFIG_SMP
+#ifndef CONFIG_SMP
 	task_thread_info(current)->l1_task_info.stack_start =
 		(void *)current->mm->context.stack_start;
 	task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;