ARM: mm: proc-mohawk: Use the new processor struct macros

This patch also defines a suitable flush_icache_all implementation
which would otherwise be missing, resulting in a link failure.
Thanks to Nicolas Pitre for suggesting the code for this.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>