drm/nouveau/ltc: drop workaround for an interrupt storm that no longer happens

This is really the wrong thing to do, but at the time it was our only
option to prevent worse issues.

We no longer cause quite so much anger from LTC, so it's not needed.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/subdev/ltc/gf100.c

@@ -87,11 +87,6 @@ gf100_ltc_intr(struct nouveau_subdev *subdev)
 			gf100_ltc_lts_isr(priv, ltc, lts);
 		mask &= ~(1 << ltc);
 	}
-
-	/* we do something horribly wrong and upset PMFB a lot, so mask off
-	 * interrupts from it after the first one until it's fixed
-	 */
-	nv_mask(priv, 0x000640, 0x02000000, 0x00000000);
 }
 
 static int

drivers/gpu/drm/nouveau/core/subdev/ltc/gm107.c

@@ -87,11 +87,6 @@ gm107_ltc_intr(struct nouveau_subdev *subdev)
 			gm107_ltc_lts_isr(priv, ltc, lts);
 		mask &= ~(1 << ltc);
 	}
-
-	/* we do something horribly wrong and upset PMFB a lot, so mask off
-	 * interrupts from it after the first one until it's fixed
-	 */
-	nv_mask(priv, 0x000640, 0x02000000, 0x00000000);
 }
 
 static int