ARM: OMAP2+: Drop unused omap_hwmod_mux_info

This is no longer used as we boot in device tree
only mode.

Cc: Lokesh Vutla <lokeshvutla@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>