ARM: mach-shmobile: kzm9g: add external USB Host support

This patch uses r8a66597_hcd driver,
since renesas_usbhs driver doesn't support external R8A66597 chip.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Simon Horman <horms@verge.net.au>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>