NXP SoCs like the iMX8QM, iMX8QXP or iMX8DXP use power domains for resource management. Add compatible strings for these SoCs (QXP and DXP gets to share as their only difference is a core-count, Q=Quad core and D=Dual core), and allow power-domains for them only. Keep the old restriction for others. Signed-off-by: John Ernberg <john.ernberg@actia.se> Reviewed-by: Rob Herring (Arm) <robh@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>