[PATCH for-mm 2/3] arch/arm64/kernel/irq: Include missed header file

[SeongJae Park <sj@kernel.org>]

Commit da4561bd9c6b ("arm64, scs: save scs_sp values per-cpu when
switching stacks") of -mm is moving declaration of
irq_shadow_call_stack_ptr to scs.h of arm64 for !SHADOW_CALL_STACK, but
didn't include it in irq.c of arm64.  As a result, we show below build
error when SHADOW_CALL_STACK is unset.

    linux/arch/arm64/kernel/irq.c: In function 'init_irq_scs':
    linux/arch/arm64/kernel/irq.c:44:11: error: 'irq_shadow_call_stack_ptr' undeclared (first use in this function)
       44 |   per_cpu(irq_shadow_call_stack_ptr, cpu) =
          |           ^~~~~~~~~~~~~~~~~~~~~~~~~

This commit fixes the build error by including the header file.

[1] https://lore.kernel.org/all/f75c58b17bfaa419f84286cd174e3a08f971b779.1648049113.git.andreyknvl@google.com/

Fixes: da4561bd9c6b ("arm64, scs: save scs_sp values per-cpu when switching stacks") of -mm
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 arch/arm64/kernel/irq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 4199f900714a..9f7de9d5ee9b 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -20,6 +20,7 @@
 #include <linux/scs.h>
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
+#include <asm/scs.h>
 #include <asm/daifflags.h>
 #include <asm/vmap_stack.h>
 
-- 
2.17.1