nvme: Enable FUA

Most NVME devcies maintain data in internal cache for an uncertain
times, and u-boot has no method to force NVME to flush cache.
So this patch adds FUA to avoid data loss caused by power off after data
programming.

Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c
index 3c529a2..9623c89 100644
--- a/drivers/nvme/nvme.c
+++ b/drivers/nvme/nvme.c
@@ -762,6 +762,10 @@
 	c.rw.appmask = 0;
 	c.rw.metadata = 0;
 
+	/* Enable FUA for data integrity if vwc is enabled */
+	if (dev->vwc)
+		c.rw.control |= NVME_RW_FUA;
+
 	while (total_lbas) {
 		if (total_lbas < lbas) {
 			lbas = (u16)total_lbas;