ARM: OMAP4: cpuidle: Configure MPU C4 state to OSWR

ARM: OMAP4: cpuidle: Configure MPU C4 state to OSWR

Due to MPU_EMIF_NO_DYNDEP_IDLE_iXXX, MPU->EMIF dynamic dependency
is disabled when going to LP mode. This allows us to enable deeper
power state for MPU as MPU can transition to lower power state
independent of core power domain. We have observed 1.5mA saving in
OS Idle Screen on use case.

Change-Id: If4ec4426626dabf810b1f21ed33cdabafa386d5f
Signed-off-by: Madhusudan Chittim <c-madhu@ti.com>