If MICROPY_FATFS_MAX_SS is defined to power of 2 value between 1024 and
4096, support for dynamic sector size in FatFs will be enabled. Note
that FatFs reserves static buffer of MICROPY_FATFS_MAX_SS size for each
filesystem in use, so that value should be set sparingly.
Initial patch provided by @pfalcon.
13a4c120ce