arm64/asm: Remove unused enable_da macro

We no longer use the enable_da macro, remove it to avoid having to think
about maintaining it.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221019120346.72289-1-broonie@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>