ARM: dts: lpc18xx: add cgu and ccu clock-controller nodes

Add CGU and CCU clock-controller nodes for lpc18xx together with
the fixed input clocks. Also remove the temporary fixed-factor
pll1 clock from both lpc18xx and lpc4350-hitex-eval DTS now that
proper clock drivers are inplace.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Acked-by: Michael Turquette <mturquette@baylibre.com>