rtlwifi/rtl8192de: Fix print format string

%ul was likely meant as %lu to print an unsigned long,
not an unsigned with a letter l at the end.
But in fact the value printed is u32 anyway, so just drop
the l completely.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>