semihosting: Fix Lesser GPL version number

semihosting: Fix Lesser GPL version number

There is no "version 2" of the "Lesser" General Public License.
It is either "GPL version 2.0" or "Lesser GPL version 2.1".
This patch replaces all occurrences of "Lesser GPL version 2" with
"Lesser GPL version 2.1" in comment section.

Signed-off-by: Chetan Pant <[email protected]>
Message-Id: <20201016144243[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Acked-by: Alex Bennée <[email protected]>
Signed-off-by: Thomas Huth <[email protected]>