wcn36xx: Remove Unicode Byte Order Mark from testcode

Older gcc (< 4.4) doesn't like files starting with a Unicode BOM:

    drivers/net/wireless/ath/wcn36xx/testmode.c:1: error: stray ‘\357’ in program
    drivers/net/wireless/ath/wcn36xx/testmode.c:1: error: stray ‘\273’ in program
    drivers/net/wireless/ath/wcn36xx/testmode.c:1: error: stray ‘\277’ in program

Remove the BOM, the rest of the file is plain ASCII anyway.

Output of "file drivers/net/wireless/ath/wcn36xx/testmode.c" before:

    drivers/net/wireless/ath/wcn36xx/testmode.c: C source, UTF-8 Unicode (with BOM) text

and after:

    drivers/net/wireless/ath/wcn36xx/testmode.c: C source, ASCII text

Fixes: 87f825e6 ("wcn36xx: Add support for Factory Test Mode (FTM)")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ramon Fried <ramon.fried@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/wcn36xx/testmode.c

-/*
+/*
  * Copyright (c) 2018, The Linux Foundation. All rights reserved.
  *
  * Permission to use, copy, modify, and/or distribute this software for any