Build the APMU for r8a7790 even though SMP is
disabled in the kernel config. Also initialize
Suspend-to-RAM from pm-r8a7790.c to in the future
cover both UP and SMP use cases of the APMU.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>