HACK: drm/msm/adv7511: Don't rely on interrupts for EDID parsing

The adv7511 driver is currently woken up on successful EDID read
after a EDID_READY interrupt is triggered by the chip. If the driver
doesn't get the interrupt within 200 ms, its concluded that we failed
to read EDID from the monitor.

This interrupt doesn't seem to occur consistently in certain use cases
(for example, if we execute power-on -> get_modes -> power-off
repeatedly, this can be done by calling xrandr successively really
fast).

For now, execute the lesser preferred POLL path where the driver
manually checks on the interrupt status register after every 25ms.

We should ideally rootcause why we don't get EDID_READY interrupts
consistently instead of relying on the above approach.

Signed-off-by: Archit Taneja <architt@codeaurora.org>