ARM: arch-shmobile: only run HDMI init on respective boards

If several boards are enabled in the kernel configuration,
hdmi_init_pm_clock() functions from board-ap4evb.c and board-mackerel.c
will run on any of them. Prevent this by calling these functions from the
.init_machine() callback instead of using device_initcall().

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Magnus Damm <damm@opensource.se>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>