Staging: wlan-ng: Fixing coding style warnings

Removes following warnings found by checkpatch.pl script:

WARNING: Prefer using '"%s...", __func__' to using 'xxx',
this function's name, in a string

Signed-off-by: Simo Koskinen <koskisoft@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>