OMAP3: PM: make omap3_cpuidle_update_states independent of enable_off_mode

Currently omap3_cpuidle_update_states makes whole sale decision
on which C states to update based on enable_off_mode variable
Instead, achieve the same functionality by independently providing
mpu and core deepest states the system is allowed to achieve and
update the idle states accordingly.

Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
[khilman: fixed additional user of this API in OMAP CPUidle driver]
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>