ARM: shmobile: sh73a0: fixup div4_clks bitmap

div4_clks's bitmap of sh73a0 was wrong.
This patch is based on v2.0 datasheet.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>