OMAP: hwmod: Fix wrong pointer iteration in oh->slaves

The iteration is currently done on the omap_hwmod_ocp_if pointer
and not on the table pointer that reference them.
It worked most of the time because the structure are contiguous in
memory.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>