fix various comments

Signed-off-by: Marcel Ziswiler <marcel@ziswiler.com>
diff --git a/nand_spl/nand_boot.c b/nand_spl/nand_boot.c
index 840a596..e2147cb 100644
--- a/nand_spl/nand_boot.c
+++ b/nand_spl/nand_boot.c
@@ -73,7 +73,7 @@
 	nand_command(mtd, block, 0, CFG_NAND_BAD_BLOCK_POS, NAND_CMD_READOOB);
 
 	/*
-	 * Read on byte
+	 * Read one byte
 	 */
 	if (this->read_byte(mtd) != 0xff)
 		return 1;