sysfs: export sysfs_remove_file_self()

Function is going to be used in transport over RDMA module in subsequent
patches, so export it to GPL modules.

Link: https://lore.kernel.org/r/20200511135131.27580-2-danil.kipnis@cloud.ionos.comSigned-off-by: NRoman Pen <roman.penyaev@profitbricks.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
[jwang: extend the commit message]
Signed-off-by: NJack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

fs/sysfs/file.c

@@ -492,6 +492,7 @@ bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
 	kernfs_put(kn);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(sysfs_remove_file_self);
 
 void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr)
 {