bsp-guide: fix branch listing command

Replace 'git branch -al' with 'git branch -a' to correctly show both
local and remote branches. The '-l' option is unnecessary and may cause
confusion.

(From yocto-docs rev: 46aa3bb398c50af0f29acd2c1a05ee232d0de5b9)

Signed-off-by: Bo Sun <bo@mboxify.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/bsp-guide/bsp.rst

@@ -204,7 +204,7 @@ section.
       .. note::
 
          To see the available branch names in a cloned repository, use the ``git
-         branch -al`` command. See the
+         branch -a`` command. See the
          ":ref:`dev-manual/start:checking out by branch in poky`"
          section in the Yocto Project Development Tasks Manual for more
          information.