dmaengine: ste_dma40_ll: Replace meaningless register set with comment

Unsure of the author's intentions, rather than just removing the nop,
we're replacing it with a comment containing the possible intention
of the statement OR:ing with 0.

Cc: Dan Williams <djbw@fb.com>
Cc: Per Forlin <per.forlin@stericsson.com>
Cc: Rabin Vincent <rabin@rab.in>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/dma/ste_dma40_ll.c

@@ -182,8 +182,10 @@ static int d40_phy_fill_lli(struct d40_phy_lli *lli,
 	else
 		lli->reg_cfg &= ~BIT(D40_SREG_CFG_TIM_POS);
 
-	/* Post link */
-	lli->reg_lnk |= 0 << D40_SREG_LNK_PHY_PRE_POS;
+	/*
+	 * Post link - D40_SREG_LNK_PHY_PRE_POS = 0
+	 * Relink happens after transfer completion.
+	 */
 
 	return 0;
 }