doc: verified-boot: fix typos

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/doc/uImage.FIT/verified-boot.txt b/doc/uImage.FIT/verified-boot.txt
index e639e7a..41c9fa9 100644
--- a/doc/uImage.FIT/verified-boot.txt
+++ b/doc/uImage.FIT/verified-boot.txt
@@ -93,7 +93,7 @@
 add signatures as well.
 
 The public key can be stored in U-Boot's CONFIG_OF_CONTROL device tree in
-a standard place. Then when a FIT it loaded it can be verified using that
+a standard place. Then when a FIT is loaded it can be verified using that
 public key. Multiple keys and multiple signatures are supported.
 
 See signature.txt for more information.