Avoid flushing buffers when seeking with SeekFrom::Start is a no-op
Avoid flushing buffers when seeking with SeekFrom::Start is a no-op

Do not flush internal buffers when seeking with SeekFrom::Start resolves
to the current position. Also removes the extra check whether the target
position falls into the buffered range as this is already handled by
seek_forward.

Signed-off-by: Tobias Rapp <cf930e65ce108ebd4073f997d861601527ad10dc@noa-archive.com>

gcarq/seek_bufread,gcarq/seek_bufread