TODO: remove outdated AT91SAM92xx entry

SAM9260 gained good generic infrastructure since 2009. And we always
want "improvements", no need for a TODO item.

Signed-off-by: Wolfram Sang <wsa@kernel.org>
Change-Id: I92551ef9d42ee47ad7441f2354587bbb45edc97e
Reviewed-on: https://review.openocd.org/c/openocd/+/7526
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

TODO

@@ -202,8 +202,6 @@ https://lists.berlios.de/pipermail/openocd-development/2009-October/011506.html
 - MC1322x support (JW/DE?)
   - integrate and test support from JW (and DE?)
   - get working with a known good interface (i.e. not today's jlink)
-- AT91SAM92xx:
-  - improvements for unknown-board-atmel-at91sam9260.cfg (RD)
 - STR9x: (ZW)
   - improvements to str912.cfg to be more general purpose
 - AVR: (SQ)