core/command: delete nvram command

Was only used for cros_ec_nvram_cb, which is now gone.

BUG=chromium:990438,chromium:1090803
TEST=compiles

Change-Id: I60518ddd98a569123abc2764d4dbb69175bbc3ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mosys/+/2469467
Tested-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
4 files changed