ARM: OMAP4+: Remove unused omap_l3_noc platform init

Omap4 and later have been booting in device tree only
mode for quite some time now. This initcall is no longer
needed. Note that omap3 uses a different driver omap_l3_smx,
and the initcall for that one is still needed until omap3
boots in device tree only mode.

Signed-off-by: Tony Lindgren <tony@atomide.com>