dts: stm32f411e_disco@B: fix wrong device label lsm303agr-magn@1e.

the device label lsm303agr-magn@1e doesn't exist in the base dts
file stm32f411e_disco.dts, it is lsm303agr-magn, so correct it.

Signed-off-by: Chen Peng1 <peng1.chen@intel.com>