platform/chrome: fix kernel-doc warnings for panic notifier

Fix the following kernel-doc warnings:

$ ./scripts/kernel-doc -none drivers/platform/chrome/*
drivers/platform/chrome/cros_ec_debugfs.c:54: warning: Function
parameter or member 'notifier_panic' not described in 'cros_ec_debugfs'

$ ./scripts/kernel-doc -none include/linux/platform_data/cros_ec_proto.h
include/linux/platform_data/cros_ec_proto.h:187: warning: Function
parameter or member 'panic_notifier' not described in 'cros_ec_device'

Cc: Rob Barnes <robbarnes@google.com>
Fixes: d90fa2c6 ("platform/chrome: cros_ec: Poll EC log on EC panic")
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groweck@chromium.org>
Link: https://lore.kernel.org/r/20230111055728.708990-2-tzungbi@kernel.org