FROMGIT: MIPS/Loongson: Fix build warnings about export.h

After commit a934a57 ("scripts/misc-check: check missing #include
<linux/export.h> when W=1") and 7d95680 ("scripts/misc-check:
check unnecessary #include <linux/export.h> when W=1"), we get some build
warnings with W=1:

arch/mips/loongson64/setup.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present

So fix these build warnings for MIPS/Loongson.

Signed-off-by: Huacai Chen <[email protected]>
Reviewed-by: Masahiro Yamada <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>

(cherry picked from commit 3376910
 https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git mips-next)
Signed-off-by: Kexy Biscuit <[email protected]>

Author: chenhuacai

arch/mips/loongson64/setup.c

@@ -3,7 +3,6 @@
  * Copyright (C) 2007 Lemote Inc. & Institute of Computing Technology
  * Author: Fuxin Zhang, [email protected]
  */
-#include <linux/export.h>
 #include <linux/init.h>
 
 #include <asm/bootinfo.h>