arm64: add Cortex-A57 erratum 832075 workaround

The ARM erratum 832075 applies to certain revisions of Cortex-A57,
one of the workarounds is to change device loads into using
load-aquire semantics.
This is achieved using the alternatives framework.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --cc arch/arm64/include/asm/cpufeature.h
Simple merge

diff --cc arch/arm64/include/asm/io.h
Simple merge

diff --cc arch/arm64/kernel/cpu_errata.c
Simple merge