ARM: OMAP2+: Remove mostly unused hwmod linkspace

We want to be able to dynamically allocate struct omap_hwmod_ocp_if and
struct omap_hwmod at device driver probe time based on .dts data.

Current setup with the linkspace using memblock_virt_alloc() makes
this tricky, so let's get rid of struct linkspace and directly set up
struct omap_hwmod_ocp_if as the master and slave lists.

As we are currently not using the master_ports either, let's remove it
too. And let's add the struct omap_hwmod_ocp_if node directly to the
slave_ports list.

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