arm64: apply ARM64_ERRATUM_845719 workaround for Brahma-B53 core
    
    The Broadcom Brahma-B53 core is susceptible to the issue described by
    ARM64_ERRATUM_845719 so this commit enables the workaround to be applied
    when executing on that core.
    
    Since there are now multiple entries to match, we must convert the
    existing ARM64_ERRATUM_845719 into an erratum list.
    
    Signed-off-by: Doug Berger <opendmb@gmail.com>
    Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
    Signed-off-by: Will Deacon <will@kernel.org>