doc: board: toradex: minor documentation update

- Update SPDX-License-Identifier from obsolete GPL-2.0+ to
  GPL-2.0-or-later.
- Add links to product websites of SoM and carrier board where missing.
- Add information about update U-Boot wrapper where missing.
- Add sectionauthor where missing.
- Update information about imx-seco from version 3.7.4 to 3.8.1.
- Various minor grammatic and spelling fixes.
- Improve whitespace by adding or removing new lines.
- Change from code-block for output to just Output::.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
diff --git a/doc/board/toradex/verdin-imx8mm.rst b/doc/board/toradex/verdin-imx8mm.rst
index cc39030..6e150e9 100644
--- a/doc/board/toradex/verdin-imx8mm.rst
+++ b/doc/board/toradex/verdin-imx8mm.rst
@@ -46,6 +46,7 @@
 
 Build U-Boot
 ------------
+
 .. code-block:: bash
 
     $ export CROSS_COMPILE=aarch64-linux-gnu-
@@ -61,7 +62,7 @@
     > setexpr blkcnt ${filesize} + 0x1ff && setexpr blkcnt ${blkcnt} / 0x200
     > mmc dev 0 1 && mmc write ${loadaddr} 0x2 ${blkcnt}
 
-As a convenience, instead of the last two commands one may also use the update
+As a convenience, instead of the last two commands, one may also use the update
 U-Boot wrapper:
 
 .. code-block:: bash
@@ -71,16 +72,14 @@
 Boot
 ----
 
-ATF, U-Boot proper and u-boot.dtb images are packed into FIT image,
+ATF, U-Boot proper and u-boot.dtb images are packed into a FIT image,
 which is loaded and parsed by SPL.
 
 Boot sequence is:
 
 * SPL ---> ATF (TF-A) ---> U-Boot proper
 
-Output:
-
-.. code-block:: none
+Output::
 
   U-Boot SPL 2021.10-rc2-00028-gee010ba1129 (Aug 23 2021 - 16:56:02 +0200)
   Normal Boot