net: nixge: fix spelling mistake in Kconfig: "Instuments" -> "Instruments"

There is a spelling mistake in the Kconfig. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20201216120020.13149-1-colin.king@canonical.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>