revert SGM noise multiplier change for img2img because it breaks hires fix

modules/sd_samplers_kdiffusion.py

@@ -144,13 +144,7 @@ class KDiffusionSampler(sd_samplers_common.Sampler):
         sigmas = self.get_sigmas(p, steps)
         sigma_sched = sigmas[steps - t_enc - 1:]
 
-        if opts.sgm_noise_multiplier:
-            p.extra_generation_params["SGM noise multiplier"] = True
-            noise_multiplier = torch.sqrt(1.0 + sigma_sched[0] ** 2.0)
-        else:
-            noise_multiplier = sigma_sched[0]
-
-        xi = x + noise * noise_multiplier
+        xi = x + noise * sigma_sched[0]
 
         if opts.img2img_extra_noise > 0:
             p.extra_generation_params["Extra noise"] = opts.img2img_extra_noise