cleanup: ignore compiled executable in extra/
cleanup: ignore compiled executable in extra/

This just adds a .gitignore entry so that git doesn't complain
about the executable you may have built in the extra/usb_console/
directory.

BUG=none
BRANCH=none
TEST=make buildall

This has no effect on the EC code at all. The things in the
extra/ directory are optional and unsupported.

Change-Id: Ib4915f712f9d14caf7418ef4b03aa41e8764fd36
Signed-off-by: Bill Richardson <129945214b1d548d8e49b6c29c43094f8c78057f@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/310840
Reviewed-by: Vadim Bendebury <5515d6d2d0829cbe0dd0dcf2094aaded06d58514@chromium.org>

akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics