Update devices.h
Update devices.h

Correct capacity value for the MX25R1635F from 0x18 to 0x15 (tested and working)
refer to 
https://github.com/adafruit/circuitpython/issues/3558
adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython