Add control pins TX_EN, RX_EN for RFM95 modules

[wanvo]

Please add control TX_EN for the transfer, and RX_EN for the receiver in the RFM95 driver. There is a powerful (1W) inexpensive module on the sx1276 chip. To switch the extra amplifier to this module, signals TX_EN, RX_EN are needed. Without these signals, the module is not working correctly, I checked.

During the receive, TX_EN = 0, RX_EN = 1,
During transmission, TX_EN = 1, RX_EN = 0,
In the sleep mode, TX_EN = 0, RX_EN = 0.

Here is a link to the documentation for it