ARM: OMAP4+: CM: Remove redundant checks for clkctrl_offs of zero

Now that we have moved the check for valid clkctrl_offs to the caller of
am33xx_cm_wait_module_ready/idle and omap4_cminst_wait_module_ready/idle
let's remove the now redundant check for clkctrl_offs from these functions.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>