[PATCH] bonding: expose some structs

The sysfs code needs to know what these structs look like, so make them
not static, and move the definition to the header.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Acked-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>