ARM: mach-shmobile: mackerel: modify LCDC clock divider value

mackerel WVGA LCDC panel expect 33.3MHz for dot-clock,
but current dot-clock was 50.0MHz.
This patch modify clock divider value.

Signed-off-by: Makoto Ueda <makoto.ueda.ub@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>