doc: board: ti: k3: Fixup alt text for openocd sequence

Fix up OpenOCD setup sequence

Fixes: effe50854a69 ("doc: board: ti: k3: Add a guide to debugging with OpenOCD")
Reported-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
diff --git a/doc/board/ti/k3.rst b/doc/board/ti/k3.rst
index 5be8fa2..445c0f5 100644
--- a/doc/board/ti/k3.rst
+++ b/doc/board/ti/k3.rst
@@ -488,6 +488,7 @@
 The overall structure of this setup is in the following figure.
 
 .. image:: img/openocd-overview.svg
+  :alt: Overview of OpenOCD setup.
 
 .. note::