MIPS: mobileye: eyeq5: use OLB as provider for fixed factor clocks

Change the structure of the clock tree: rather than individual
devicetree nodes registering each fixed factor clock derived from OLB
PLLs, have the OLB node provide the necessary clocks.

Remove eyeq5-clocks.dtsi and move the three remaining "fixed-clock"s to
the main eyeq5.dtsi file.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>