staging: r8188eu: Fixed a function declaration coding style issue

Added an identifier name for function definition argument
'struct timer_list *' as per checkpatch.pl

Note that for the same line checkpatch.pl will also complain "extern
should be avoided in .c". I am not very familiar with the codebase
so I decided not to move the declaration to a header file.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Chang Yu <marcus.yu.56@gmail.com>
Link: https://lore.kernel.org/r/778c21724752f2de136d82b31c9ffc2bf35ced55.1655872968.git.marcus.yu.56@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_recv.c

@@ -24,7 +24,7 @@ static u8 rtw_rfc1042_header[] = {
        0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00
 };
 
-void rtw_signal_stat_timer_hdl(struct timer_list *);
+void rtw_signal_stat_timer_hdl(struct timer_list *t);
 
 void _rtw_init_sta_recv_priv(struct sta_recv_priv *psta_recvpriv)
 {