devlink: add devl guard

Add devl guard for scoped_guard().

Example usage:

scoped_guard(devl, priv_to_devlink(pf)) {
	err = init_devlink(pf);
	if (err)
		return err;
}

Co-developed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Konrad Knitter <konrad.knitter@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Author: konradknitter

include/net/devlink.h

@@ -1535,6 +1535,7 @@ int devl_trylock(struct devlink *devlink);
 void devl_unlock(struct devlink *devlink);
 void devl_assert_locked(struct devlink *devlink);
 bool devl_lock_is_held(struct devlink *devlink);
+DEFINE_GUARD(devl, struct devlink *, devl_lock(_T), devl_unlock(_T));
 
 struct ib_device;