nds32: unexport flush_icache_page

flush_icache_page is only used by mm/memory.c.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Link: http://lkml.kernel.org/r/20200515143646.3857579-3-hch@lst.deSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/nds32/mm/cacheflush.c

@@ -35,7 +35,6 @@ void flush_icache_page(struct vm_area_struct *vma, struct page *page)
 	kunmap_atomic((void *)kaddr);
 	local_irq_restore(flags);
 }
-EXPORT_SYMBOL(flush_icache_page);
 
 void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
 	                     unsigned long addr, int len)