zephyr: volteer: enable BOARD_RESET_AFTER_POWER_ON
zephyr: volteer: enable BOARD_RESET_AFTER_POWER_ON

This enables BOARD_RESET_AFTER_POWER_ON feature for volteer.

BUG=b:178101173
BRANCH=None.
TEST=zmake testall
TEST=check the following reset cause
1. power-up
2. reset-pin reset

Signed-off-by: Wealian Liao <b980917544b235741b592c0c8e1e53fb264e55ff@nuvoton.corp-partner.google.com>
Change-Id: Ie1b0fc4b41227bc23d6a58e62af5e35e6f154ad3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2771130
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Reviewed-by: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Commit-Queue: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>

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