bus: omap_l3_noc: remove iclk from omap_l3 struct

we do not use iclk directly anymore. And, even if we had to, we
should be using pm_runtime APIs to do the same to be completely SoC
independent.

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Darren Etheridge <detheridge@ti.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>