[PATCH] ARC: export clear_user_page() for modules

[Randy Dunlap]

0day bot reports a build error:
  ERROR: modpost: "clear_user_page" [drivers/media/v4l2-core/videobuf-dma-sg.ko] undefined!
so export it in arch/arc/ to fix the build error.

In most ARCHes, clear_user_page() is a macro. OTOH, in a few
ARCHes it is a function and needs to be exported.
PowerPC exported it in 2004. It looks like nds32 and nios2
still need to have it exported.

Fixes: 4102b53392d63 ("ARC: [mm] Aliasing VIPT dcache support 2/4")
Signed-off-by: Randy Dunlap <rdunlap at infradead.org>
Reported-by: kernel test robot <lkp at intel.com>
Cc: Guenter Roeck <linux at roeck-us.net>
Cc: Vineet Gupta <vgupta at kernel.org>
Cc: linux-snps-arc at lists.infradead.org
---
 arch/arc/mm/cache.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20210816.orig/arch/arc/mm/cache.c
+++ linux-next-20210816/arch/arc/mm/cache.c
@@ -1041,7 +1041,7 @@ void clear_user_page(void *to, unsigned
 	clear_page(to);
 	clear_bit(PG_dc_clean, &page->flags);
 }
-
+EXPORT_SYMBOL(clear_user_page);
 
 /**********************************************************************
  * Explicit Cache flush request from user space via syscall