cmd: fuse: Add fuse writebuff sub-system command

Add CMD_FUSE_WRITEBUFF config option to add and enable fuse writebuff
sub-system command. Add fuse_writebuff function to be invoked on
writebuff command.

Signed-off-by: Harsha Vardhan V M <h-vm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
3 files changed