Remove 0x prefix from clkctrl unit address.

This silences the following dtc warning:
Warning (unit_address_format):
 Node /clkctrl@0xf8000000 unit name should not have leading "0x"
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>