ARM: appropriate __init annotation for const data

Init data marked const should be annotated with __initconst for
correctness and not __initdata.  In some cases the array gathering
references to that data has to be marked const as well. This fixes
LTO builds that otherwise fail with section mismatch errors.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>