ARM: shmobile: mackerel: Make domain_devices[] static __initdata

Make the domain_devices[] array static and __initdata, to reduce kernel
size:
  - Making it static gets rid of the code to copy the data to the stack,
  - Marking it __initdata allows more init memory to be freed.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>