ARM: shmobile: Introduce per-CPU SMP boot / sleep code

Add per-CPU SMP boot / sleep code that can be used by all
SoCs included in mach-shmobile.

The boot code reads out the per-CPU MPIDR id value and
matches it with the value stored for any CPU number, and
if there is a match and the boot function is set as well
then the boot function will be executed.

The sleep code simply uses WFI and then jumps back to the
boot code to see if anyone has asked to wake up that CPU,
if not it will sleep again.

Signed-off-by: Magnus Damm <damm@opensource.se>
[horms+renesas@verge.net.au: Remove trailing whitespace]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>