ARM: OMAP4+: CM: remove omap4_cm1/cm2_* functions

These are not used for anything, so remove both the implementations and
header file references.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>