dt-bindings: ata: Drop unneeded quotes

Cleanup bindings dropping unneeded quotes. Once all these are fixed,
checking for this can be enabled in yamllint.

Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/20230327170053.4100949-1-robh@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>