zephyr: Add support for CONFIG_POWER_BUTTON/X86
zephyr: Add support for CONFIG_POWER_BUTTON/X86

These options do not seem to be needed for correct operation since
there are no #ifdefs that use them. Still, we should add them for
completeness and in case something changes.

BUG=b:177604307
BRANCH=none
TEST=build volteer for zephyr
make BOARD=volteer -j8

Signed-off-by: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>
Change-Id: I9afe5af942a6001b3dc7b90fa6f53222e122d7f3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2643618
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