move rak to nrf52_core, remove nrf52840_core

variants/rak4631/platformio.ini

@@ -1,9 +1,9 @@
 [rak4631]
-extends = nrf52840_base
+extends = nrf52_base
 platform = https://github.com/maxgerhardt/platform-nordicnrf52.git#rak
 board = wiscore_rak4631
 board_check = true
-build_flags = ${nrf52840_base.build_flags}
+build_flags = ${nrf52_base.build_flags}
   -I variants/rak4631
   -D RAK_4631
   -D PIN_BOARD_SCL=14
@@ -14,10 +14,10 @@ build_flags = ${nrf52840_base.build_flags}
   -D LORA_TX_POWER=22
   -D SX126X_CURRENT_LIMIT=140
   -D SX126X_RX_BOOSTED_GAIN=1
-build_src_filter = ${nrf52840_base.build_src_filter}
+build_src_filter = ${nrf52_base.build_src_filter}
   +<../variants/rak4631>
 lib_deps =
-  ${nrf52840_base.lib_deps}
+  ${nrf52_base.lib_deps}
   adafruit/Adafruit SSD1306 @ ^2.5.13
   stevemarple/MicroNMEA @ ^2.0.6
 
@@ -55,7 +55,7 @@ build_flags =
 build_src_filter = ${rak4631.build_src_filter}
   +<helpers/ui/SSD1306Display.cpp>
   +<../examples/simple_repeater>
-lib_deps = 
+lib_deps =
   ${rak4631.lib_deps}
   sparkfun/SparkFun u-blox GNSS Arduino Library @ ^2.2.27
   https://github.com/boschsensortec/Bosch-BSEC2-Library