drm/i915/ehl: Remove require_force_probe protection

drm/i915/ehl: Remove require_force_probe protection

Removing force probe protection from EHL platform. Did
not observe warnings, errors, flickering or any visual
defects while doing ordinary tasks like browsing and
editing documents in a two monitor setup.

For more info drm-tip idle run results :
https://intel-gfx-ci.01.org/tree/drm-tip/drmtip.html?

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210629104954.927151-1-tejaskumarx.surendrakumar.upadhyay@intel.com