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: 297ae1eb ("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.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/Kconfig

@@ -672,6 +672,7 @@ config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
 
 config ARM64_ERRATUM_2051678
 	bool "Cortex-A510: 2051678: disable Hardware Update of the page table dirty bit"
+	default y
 	help
 	  This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678.
 	  Affected Coretex-A510 might not respect the ordering rules for