configs/orangepi_r1_defconfig: fix typo in comment

In commit 38d04e6b1341, I did a last-minute change by adding the comment
to explain where the PARTLABEL was coming from, and introduced a typo in
that comment.

Fix it.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

board/orangepi/orangepi-r1/genimage.cfg

@@ -33,7 +33,7 @@ image sdcard.img {
 	}
 
 	# 'rootfs' will be used as the partition label, used
-	# with root=PARTLABEL=rootfs kernel commadn line
+	# with root=PARTLABEL=rootfs kernel command line
 	partition rootfs {
 		partition-type = 0x83
 		image = "rootfs.ext4"