sh: sh7724: Update FSI/SPU2 clock

When FSI and Network (= NFS file system) were used at the same time,
the I/O of FSI was unstable.  This patch updates the SPU2 clock (which
is used for FSI) to solve this issue.  Special thanks to Jeremy.

Signed-off-by: Jeremy Baker <Jeremy.Baker@renesas.com>
Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>