drm/i915/dp: change aux_ctl reg read to polling read

drm/i915/dp: change aux_ctl reg read to polling read

The busy timeout logic checks for the AUX BUSY, then waits for the
timeout period and then after timeout reads the register for BUSY or
Success.
Instead replace interrupt with polling so as to read the AUX CTL
register often before the timeout period. Looks like there might be some
issue with interrupt-on-read. Hence changing the logic to polling read.

v2: replace interrupt with polling read
v3: use usleep_rang instead of msleep, updated commit msg
v4: use intel_wait_for_regiter internal function
v5: use __intel_de_wait_for_register with 500us slow and 10ms fast timeout
v6: check return value of __intel_de_wait_for_register
v7: using default 2us for intel_de_wait_for_register

Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221221033209.1284435-1-arun.r.murthy@intel.com