Revert "arm64: Mitigate MTE issues with str{n}cmp()"

Revert "arm64: Mitigate MTE issues with str{n}cmp()"

This reverts commit cc895489d115f67c183d538ac5b45337acbfbc62.

Now that the str{n}cmp functions have been updated to handle MTE
properly, the workaround to use the generic functions is no longer
needed.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220301101435.19327-4-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>