staging: rtl8188eu: core: fixed msleep < 20ms can sleep for up to 20ms warning in rtw_efuse.c

This patch fixes following checkpatch.pl warning:
WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt

Signed-off-by: Jiayi Ye <yejiayily@gmail.comi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>