[4.19] i2400m fixes

Please pick the following commits for the 4.19 branch:

2507e6ab7a9a wimax: i2400: fix memory leak 6f3ef5c25cc7 wimax: i2400: Fix memory leak in i2400m_op_rfkill_sw_toggle

I previously sent these to you for other stable branches, but accidentally missed 4.19.

Ben.