clk: eyeq: add EyeQ6H central fixed factor clocks

clk: eyeq: add EyeQ6H central fixed factor clocks

Previous setup was:
 - pll-cpu clock registered from driver at of_clk_init();
 - occ-cpu clock registered from DT using fixed-factor-clock compatible.

Now that drivers/clk/clk-eyeq.c supports registering fixed factors, use
that capability to register occ-cpu.

Also switch from hard-coded index 0 for pll-cpu to using the
EQ6HC_CENTRAL_PLL_CPU constant by exposed dt-bindings headers.

occ-cpu is exposed at of_clk_init() because it gets used by both the DT
CPU nodes and the GIC timer.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20241106-mbly-clk-v2-7-84cfefb3f485@bootlin.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>