clk: imxrt: Use dts for anatop base address

In Linux IMX and IMXRT use the device tree to hold the anatop address.
The anatop is used in clock drivers as it controls the internal PLLs
This will move the macro from asm/arch-imxrt to the device tree.
This presumably should also be done with the other IMX boards as well.

Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>