The fixed clocks are registered from devicetree. Therefore the code path is
not needed, but would instead register the clocks twice, which leads to the
error message:

	clk_register clk f2s_periph_ref_clk is already registered, skipping!
	of_clk_init: failed to init clock for /soc/clkmgr@ffd04000/clocks/f2s_periph_ref_clk: 1
	clk_register clk osc1 is already registered, skipping!
	of_clk_init: failed to init clock for /soc/clkmgr@ffd04000/clocks/osc1: 1

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>