MIPS: mm: c-r4k: Flush scache to avoid cache aliases

There is a chance for the secondary cache to have memory
aliases. This can happen if the bootloader is in a non-EVA mode
(or even in EVA mode but with different mapping from the kernel)
and the kernel switching to EVA afterwards. It's best to flush
the icache to avoid having the secondary CPUs fetching stale
data from it.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>