zmake: add NPCX monitor to output packer list
zmake: add NPCX monitor to output packer list

Add the NPCX monitor binary to the output directory when using the NPCX
output packer.

BUG=b:197162681
BRANCH=none
TEST=Build zephyr for volteer, verify npcx_monitor.bin is present in the
output directory with the zephyr.bin image.

Signed-off-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Change-Id: I5ab29a797830b6870df5b86e70ebe86a62ff430b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3122866
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Reviewed-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec