Export kmap_atomic_pfn for DRM-GEM.

The driver would like to map IO space directly for copying data in when
appropriate, to avoid CPU cache flushing for streaming writes.
kmap_atomic_pfn lets us avoid IPIs associated with ioremap for this process.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

arch/x86/mm/highmem_32.c

@@ -137,6 +137,7 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
 
 	return (void*) vaddr;
 }
+EXPORT_SYMBOL_GPL(kmap_atomic_pfn); /* temporarily in use by i915 GEM until vmap */
 
 struct page *kmap_atomic_to_page(void *ptr)
 {