ARM: shmobile: r8a7740: add A3SP pm domain support

This patch adds basic A3SP pm domain support.
Now, below devices can be controled by PM

DMAC1/2/3, IPMMU, DDM, FLCTL, SYS-HPB, BBIF1, MSIOF1/2,
SCIFA,SCIFB, IIC1, IrDA, USBH, USBDMAC, SDHI0/1/2, TPU,
DREQPAK (Sys),  MMCIF, RSPI, SIM, USBF

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