reset: uniphier-glue: Add AHCI reset control support in glue layer

Add a reset line included in AHCI glue layer to enable AHCI core
implemented in UniPhier SoCs.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>