drm/nouveau: fix typo on mxmdcb option

Signed-off-by: Ben Skeggs <[e-mail]>

drivers/gpu/drm/nouveau/nouveau_drv.c

···
 int nouveau_ctxfw;
 module_param_named(ctxfw, nouveau_ctxfw, int, 0400);
 
-MODULE_PARM_DESC(ctxfw, "Santise DCB table according to MXM-SIS\n");
+MODULE_PARM_DESC(mxmdcb, "Santise DCB table according to MXM-SIS\n");
 int nouveau_mxmdcb = 1;
 module_param_named(mxmdcb, nouveau_mxmdcb, int, 0400);