tcl/board: Move nordic configuration files

Move board configuration files into a dedicated vendor directory as
required by the new guideline for configuration files.

Change-Id: Icbf368d7a453c82813e685d2935b186eb738c3ea
Signed-off-by: Marc Schink <dev@zapb.de>
Reviewed-on: https://review.openocd.org/c/openocd/+/8864
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

diff --git a/tcl/board/nordic_nrf51_dk.cfg b/tcl/board/nordic/nrf51-dk.cfg
similarity index 100%
rename from tcl/board/nordic_nrf51_dk.cfg
rename to tcl/board/nordic/nrf51-dk.cfg

diff --git a/tcl/board/nordic_nrf51822_mkit.cfg b/tcl/board/nordic/nrf51822-mkit.cfg
similarity index 100%
rename from tcl/board/nordic_nrf51822_mkit.cfg
rename to tcl/board/nordic/nrf51822-mkit.cfg

diff --git a/tcl/board/nordic_nrf52_dk.cfg b/tcl/board/nordic/nrf52-dk.cfg
similarity index 100%
rename from tcl/board/nordic_nrf52_dk.cfg
rename to tcl/board/nordic/nrf52-dk.cfg