ARM: 7609/1: disable errata work-arounds which access secure registers

In order to support secure and non-secure platforms in multi-platform
kernels, errata work-arounds that access secure only registers need to
be disabled. Make all the errata options that fit in this category
depend on !CONFIG_ARCH_MULTIPLATFORM.

This will effectively remove the errata options as platforms are
converted over to multi-platform.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>