staging: rtl8188eu: Replace function name in string with __func__

Replace hard coded function name FillH2CCmd_88E with __func__
and break the line to avoid more then 80 characters line.
Issue found using checkpatch.pl

Signed-off-by: Dafna Hirschfeld <dafna3@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>