arm64: Enable Cortex-A510 erratum 2051678 by default

arm64: Enable Cortex-A510 erratum 2051678 by default

The recently added configuration option for Cortex A510 erratum 2051678 does
not have a "default y" unlike other errata fixes. This appears to simply be
an oversight since the help text suggests enabling the option if unsure and
there's nothing in the commit log to suggest it is intentional.

Fixes: 69d67fb0117c ("arm64: cpufeature: List early Cortex-A510 parts as having broken dbm")
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220201144838.20037-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>