OMAP4: powerdomain: l4per pwrdm does not support OFF

The l4per power domain in ES2.0 does support only RET and ON states.
The previous ES1.0 HW database was wrong and thus fixed on ES2.
Change the pwrsts field to reflect that.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Acked-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>