drm/i915: Remove the drm_dbg() from the vblank evade critical section

drm/i915: Remove the drm_dbg() from the vblank evade critical section

We are inside the vblank evade critical section here, racing
against the raster beam. There is no time to print debug
messages.

Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Juston Li <juston.li@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211006235704.28894-4-ville.syrjala@linux.intel.com
Reviewed-by: Juston Li <juston.li@intel.com>