test: dm: Update test for LED activity and boot

Update test for LED activity and boot to follow new implementation with
property set to the LED node phandle.

Also update a copy-paste error in the function name for the activity
tests and actually enable the test with the DM_TEST macro.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2 files changed