staging: rtl8188eu: core: rtw_mlme_ext.c: Remove unused function

Remove the function NULL_hdl() that is not used anywhere.

This was partially found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/staging/rtl8188eu/core/rtw_mlme_ext.c
Simple merge

diff --cc drivers/staging/rtl8188eu/include/rtw_mlme_ext.h
Simple merge