ARM: OMAP3: PM: cleanup cam_pwrdm leftovers

ARM: OMAP3: PM: cleanup cam_pwrdm leftovers

commit e7410cf7 (02fdb03e69699f26e1370d0e51593dbc8a4e5265) moved
mangement of cam_pwrdm to CPUidle but left some remnants behind,
namely the call to clkcm_allo_idle() for the clockdomains in the MPU
pwrdm.  Remove these since they are not necessary and cause unwanted
latency in the idle path.

Acked-by: Tero Kristo <Tero Kristo <t-kristo@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>