bsp-guide: Fixed build error.

I accidently submitted this with a build error.

(From yocto-docs rev: 44b659aa7fa1dca96cb38cd272ea96e20b94aadb)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/bsp-guide/bsp.xml

@@ -696,7 +696,7 @@
             Furthermore, there are machine-specific settings used
             during the build that are defined by the
             <filename>machconfig</filename> file further down in
-            the directory (i.e. <filename>formfactor/rpi/).
+            the directory (i.e. <filename>formfactor/rpi/</filename>).
             Here is the <filename>machconfig</filename> file for
             the Raspberry Pi BSP:
             <literallayout class='monospaced'>