mtd: rawnand: meson: only initialize the RB completion once

Documentation/scheduler/completion.txt states:
  Calling init_completion() on the same completion object twice is
  most likely a bug as it re-initializes the queue to an empty queue and
  enqueued tasks could get "lost" - use reinit_completion() in that case,
  but be aware of other races.

Initialize nfc->completion in meson_nfc_probe using init_completion and
change the call in meson_nfc_queue_rb to reinit_completion so the logic
matches what the documentation suggests.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Liang Yang <liang.yang@amlogic.com>
Acked-by: Liang Yang <liang.yang@amlogic.com>
Tested-by: Liang Yang <liang.yang@amlogic.com>
Acked-by: Liang Yang <liang.yang@amlogic.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/meson_nand.c

@@ -400,7 +400,7 @@ static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
 	cfg |= NFC_RB_IRQ_EN;
 	writel(cfg, nfc->reg_base + NFC_REG_CFG);
 
-	init_completion(&nfc->completion);
+	reinit_completion(&nfc->completion);
 
 	/* use the max erase time as the maximum clock for waiting R/B */
 	cmd = NFC_CMD_RB | NFC_CMD_RB_INT
@@ -1380,6 +1380,7 @@ static int meson_nfc_probe(struct platform_device *pdev)
 
 	nand_controller_init(&nfc->controller);
 	INIT_LIST_HEAD(&nfc->chips);
+	init_completion(&nfc->completion);
 
 	nfc->dev = dev;