zephyr: Add strzcpy()
zephyr: Add strzcpy()

This function is needed by the host-command code. Add it.

BUG=b:177065174, b:172678200
BRANCH=none
TEST=build & boot EC for Volteer
0x0d & 0xa4 don't have error message.
21-01-11 16:42:09.226 [1.528500 HC 0x0d]
21-01-11 16:42:09.227 [1.532100 HC 0xa4]

Signed-off-by: Wealian Liao <b980917544b235741b592c0c8e1e53fb264e55ff@nuvoton.corp-partner.google.com>
Change-Id: I135b510b66b1135a3c35e360588b44e33e19c85b
Signed-off-by: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2620730
Tested-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Commit-Queue: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>

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