soc: ti: omap-prm: poll for reset complete during de-assert

Poll for reset completion status during de-assertion of reset, otherwise
the IP in question might be accessed before it has left reset properly.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>