Add RADIOLIB_EXCLUDE_LR2021 in places that excluded LR11x0 (#10112)

To save resources, some devices where LR11x0 was never an option
excluded it from compilation, using RADIOLIB_EXCLUDE_LR11X0 .

As we will soon have LR2021 support, apply the same treatment
to that chip to these devices, by adding RADIOLIB_EXCLUDE_LR2021

variants/nrf52840/rak4631_epaper/platformio.ini

@@ -11,6 +11,7 @@ build_flags = ${nrf52840_base.build_flags}
   -DRADIOLIB_EXCLUDE_SX128X=1
   -DRADIOLIB_EXCLUDE_SX127X=1
   -DRADIOLIB_EXCLUDE_LR11X0=1
+  -DRADIOLIB_EXCLUDE_LR2021=1
 build_src_filter = ${nrf52_base.build_src_filter} +<../variants/nrf52840/rak4631_epaper>
 lib_deps = 
   ${nrf52840_base.lib_deps}