drivers: doxygen cleanup

drivers/adcxx1c/adcxx1c_saul.c

drivers/adcxx1c/include/adcxx1c_params.h

drivers/adcxx1c/include/adcxx1c_regs.h

drivers/adxl345/include/adxl345_params.h

drivers/adxl345/include/adxl345_regs.h

drivers/at30tse75x/at30tse75x.c

drivers/at86rf2xx/include/at86rf2xx_params.h

drivers/at86rf2xx/include/at86rf2xx_registers.h

drivers/bh1750fvi/include/bh1750fvi_internal.h

drivers/bh1750fvi/include/bh1750fvi_params.h

drivers/bmp180/include/bmp180_internals.h

drivers/bmp180/include/bmp180_params.h

drivers/bmx280/bmx280_saul.c

drivers/bmx280/include/bmx280_internals.h

drivers/bmx280/include/bmx280_params.h

drivers/cc110x/include/cc110x-defaultsettings.h

drivers/cc110x/include/cc110x-defines.h

drivers/cc110x/include/cc110x-interface.h

drivers/cc110x/include/cc110x-internal.h

drivers/cc110x/include/cc110x-netdev.h