drm/i915/display/psr: Fix cppcheck warnings

Fix redundant condition, caught in cppcheck by kernel test robot.
Reported-by: kernel test robot <lkp@intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Fixes: b64d6c51 ("drm/i915/display: Support PSR Multiple Instances")
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Harish Chegondi <harish.chegondi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210409231738.238682-1-jose.souza@intel.com

drivers/gpu/drm/i915/display/intel_psr.c

@@ -1518,8 +1518,7 @@ void intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state)
 		u32 psr_status;
 
 		mutex_lock(&intel_dp->psr.lock);
-		if (!intel_dp->psr.enabled ||
-		    (intel_dp->psr.enabled && intel_dp->psr.psr2_enabled)) {
+		if (!intel_dp->psr.enabled || intel_dp->psr.psr2_enabled) {
 			mutex_unlock(&intel_dp->psr.lock);
 			continue;
 		}