Remove standard RFM69

Author: Šlajs Václav

.gitmodules

@@ -1,9 +1,6 @@
 [submodule "libraries/yi-play-firmata"]
 	path = libraries/yi-play-firmata
 	url = https://github.com/ysoftiota/yi-play-firmata
-[submodule "libraries/RFM69"]
-	path = libraries/RFM69
-	url = https://github.com/LowPowerLab/RFM69
 [submodule "libraries/SPIFlash"]
 	path = libraries/SPIFlash
 	url = https://github.com/LowPowerLab/SPIFlash