arm64: apply ARM64_ERRATUM_843419 workaround for Brahma-B53 core

The Broadcom Brahma-B53 core is susceptible to the issue described by
ARM64_ERRATUM_843419 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_843419 into an erratum list and use
cpucap_multi_entry_cap_matches to match our entries.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Will Deacon <will@kernel.org>