lib/genalloc.c: export symbol addr_in_gen_pool

We use addr_in_gen_pool() in a driver module.  So export it.

Link: http://lkml.kernel.org/r/20181224070622.22197-2-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Skidanov <alexey.skidanov@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/genalloc.c b/lib/genalloc.c
index 24d20ca..af9a574 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -567,6 +567,7 @@
 	rcu_read_unlock();
 	return found;
 }
+EXPORT_SYMBOL(addr_in_gen_pool);
 
 /**
  * gen_pool_avail - get available free space of the pool