boards.cfg: remove trailing whitespace

Commit 93e14596 "Coding Style cleanup: replace leading SPACEs by TABs"
added trailing whitespace to a single line of boards.cfg. I presume this
was unintentional, and it causes the file to change after running it
through the reformat.py script. Remove the offending character.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>