The current logic attempts to send `CMD_SET_TX_POWER` before saving the new power setting. If `CMD_SET_TX_POWER` fails the power setting will not get saved. As a result, when the RFC is powered off, all attempts to change TX power will fail.
This commit changes this logic to always save the new TX setting as requested by the user. If the RFC is powered up, we apply it immediately. If it is powered down, the new setting will automatically be applied next time we send `CMD_RADIO_SETUP`.
Fixes#1340
f401c7cc60