i.MX6SX has a PCI power domain in PGC. Add support for it.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Acked-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>