This extra clock is needed to access the registers of the XOR engine
controller used on CP110 component of the Armada 7K/8K SoCs.

This follow the changes already made in the binding documentation (as
well as in the driver): "dmaengine: mv_xor_v2: Fix clock resource by
adding a register clock"
Signed-off-by: NGregory CLEMENT <gregory.clement@bootlin.com>