ARM: 6829/1: amba: make hardcoded periphid override hardware

This makes a hardcoded periphid from the platform override any
magic number found in the hardware. This shall henceforth be used
when the information found in the hardware is either missing,
i.e. not encoding the CID with the magic cookie 0xb105f00d, or
incorrect such that the revision number should have been bumped in
hardware, but the silicon designer has failed to do so.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>