Removed NimNLE compiler warnings

[t-pi]

Clean & build, only remaining warnings are from espressif framework

Compiling .pio\build\geiger\FrameworkArduino\esp32-hal-timer.c.o
C:\users\tjalf\.platformio\packages\framework-arduinoespressif32\cores\esp32\esp32-hal-spi.c: In function 'spiTransferBytesNL':
C:\users\tjalf\.platformio\packages\framework-arduinoespressif32\cores\esp32\esp32-hal-spi.c:922:39: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]
                 uint8_t * last_out8 = &result[c_longs-1];
                                       ^
C:\users\tjalf\.platformio\packages\framework-arduinoespressif32\cores\esp32\esp32-hal-spi.c:923:40: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]
                 uint8_t * last_data8 = &last_data;
                                        ^
Compiling .pio\build\geiger\FrameworkArduino\esp32-hal-touch.c.o

[t-pi]

Adresses #425

[t-pi]

...and shows the 0x2901 description strings for the BLE characteristics in e.g. nRF Connect again, as intended (i.e. was also a bug fix)