arm64: smp: remove pointless secondary_data maintenance

arm64: smp: remove pointless secondary_data maintenance

All reads and writes of secondary_data occur with the MMU on, using
coherent attributes, so there's no need to perform any cache maintenance
for this.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210520115031.18509-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>