Add the fsinfo command to display filesystem statistics including block
size, total blocks, used blocks, and free blocks. Both raw byte counts
and human-readable sizes are shown.
Example output:
=> fsinfo mmc 0:1
Block size: 4096 bytes
Total blocks: 16384 (67108864 bytes, 64 MiB)
Used blocks: 2065 (8458240 bytes, 8.1 MiB)
Free blocks: 14319 (58650624 bytes, 55.9 MiB)
Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>