fbdev: sh_mipi_dsi: fixup setup timing of sh_mipi_setup()

sh_mipi_setup() should be called after setting of CPG

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>