Revert "nouveau/bios: Fix tracking of BIOS image data"

This reverts commit d06221c0.

It turns out to trigger the "BUG_ON(!PageCompound(page))" in kfree(),
apparently because the code ends up trying to free somethng that was
never kmalloced in the first place.

BenH points out that the patch was untested and wasn't meant to go into
the upstream kernel that quickly in the first place.

Backtrace:
  bios_shadow
  bios_shadow_prom
  nv_mask
  init_io
  bios_shadow
  nouveau_bios_init
  NVReadVgaCrtc
  NVSetOwner
  nouveau_card_init
  nouveau_load
Reported-by: NMeelis Roos <mroos@linux.ee>
Requested-by: NDave Airlie <airlied@gmail.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -273,7 +273,6 @@ bios_shadow(struct drm_device *dev)
 		mthd->score = score_vbios(bios, mthd->rw);
 		mthd->size = bios->length;
 		mthd->data = bios->data;
-		bios->data = NULL;
 	} while (mthd->score != 3 && (++mthd)->shadow);
 
 	mthd = shadow_methods;
@@ -282,8 +281,7 @@ bios_shadow(struct drm_device *dev)
 		if (mthd->score > best->score) {
 			kfree(best->data);
 			best = mthd;
-		} else
-			kfree(mthd->data);
+		}
 	} while ((++mthd)->shadow);
 
 	if (best->score) {