gpu: ipu-v3: pre: implement workaround for ERR009624

gpu: ipu-v3: pre: implement workaround for ERR009624

The PRE has a bug where a software write to the CTRL register can block
the setting of the ENABLE bit by the hardware in auto repeat mode. When
this happens the PRE will fail to handle new jobs. To work around this
software must not write to CTRL register when the PRE store engine is
inside the unsafe window, where a hardware update to the ENABLE bit
may happen.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
[p.zabel@pengutronix.de: rebased before PRE tiled prefetch support]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>