[PATCH v2] seqlock: Fix build errors

[Xingxing Su]

Fix the following build errors:

In file included from ./include/linux/time.h:6:0,
                 from ./include/linux/compat.h:10,
                 from arch/mips/kernel/asm-offsets.c:12:
./include/linux/seqlock.h: In function ‘write_seqcount_begin_nested’:
./include/linux/seqlock.h:286:2: error: implicit declaration of function 
 ‘raw_smp_processor_id’ [-Werror=implicit-function-declaration]
  lockdep_assert_preemption_disabled();
  ^
./arch/mips/include/asm/smp.h: At top level:
./arch/mips/include/asm/smp.h:28:19: error: static declaration of 
 ‘raw_smp_processor_id’ follows non-static declaration
 static inline int raw_smp_processor_id(void)
                 ^
cc1: some warnings being treated as errors
scripts/Makefile.build:117: recipe for target 'arch/mips/kernel/asm-offsets.s' failed
make[1]: *** [arch/mips/kernel/asm-offsets.s] Error 1
arch/mips/Makefile:396: recipe for target 'archprepare' failed
make: *** [archprepare] Error 2


Signed-off-by: Xingxing Su <suxingxing@xxxxxxxxxxx>
---
 v2:  update the commit message

 include/linux/seqlock.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 54bc204..4763c13 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -17,6 +17,7 @@
 #include <linux/lockdep.h>
 #include <linux/compiler.h>
 #include <linux/kcsan-checks.h>
+#include <linux/smp.h>
 #include <asm/processor.h>
 
 /*
-- 
2.1.0