UPSTREAM: arm64: include alternative handling in dcache_by_line_op

The newly introduced dcache_by_line_op macro is used at least in
one occassion at the moment to issue a "dc cvau" instruction,
which is affected by ARM errata 819472, 826319, 827319 and 824069.
Change the macro to allow for alternative patching in there to
protect affected Cortex-A53 cores.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[catalin.marinas@arm.com: indentation fixups]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Change-Id: I450594dc311b09b6b832b707a9abb357608cc6e4
(cherry picked from commit 823066d9)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>