POSIX.1 says:
> read() attempts to read up to count bytes from file descriptor fd
> into the buffer starting at buf.
On the other hand, for rt_device_read, the `@size` is defined as the
number of unit (block size for blk device, otherwise one byte).
Changes:
- Transferred unit size from POSIX R/W(in bytes) to rt_device_R/W during
request of file R/W operations.
Signed-off-by: Shell <smokewood@qq.com>
e763e51e49