Update the r8a7779 CPU Hotplug code to use SCU PSR
to wait for the target CPU core. Previously the
shared code in hotplug.c was used to let cpu_kill()
wait for cpu_die(). With this change in place the
r8a7779 SMP code does not depend on hotplug.c anymore.
Signed-off-by: Magnus Damm <damm@opensource.se> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>