net: wireless: sme.c: delete duplicated word

Drop the repeated word "is".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
Link: https://lore.kernel.org/r/20200822231953.465-7-rdunlap@infradead.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>