ARM: mvebu: clk: remove cpuclk resources overlapping coredivclk registers on Armada XP

The resources of the cpuclk node are overlapping the one from
coredivclk node. It was not noticed until now because the driver did a
simple of_iomap and not a request_mem_region. This patch fixes it.

[gregory.clement@free-electrons.com: add commit log and port to 4.0-rc]
Signed-off-by: Nadav Haklai <nadavh@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>