Staging: rtl8188eu: core: Fix coding style issue

This fixes the following checkpatch.pl warning
WARNING: Prefer using '"%s...", __func__' to using 'rtw_tkip_decrypt', this function's name, in a string.
Signed-off-by: Anoop S <anoop.skumar1507@gmail.com>
Link: https://lore.kernel.org/r/20200718103125.62528-1-anoop.skumar1507@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/core/rtw_security.c

@@ -718,7 +718,7 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, u8 *precvframe)
 				res = _FAIL;
 			}
 		} else {
-			RT_TRACE(_module_rtl871x_security_c_, _drv_err_, ("rtw_tkip_decrypt: stainfo==NULL!!!\n"));
+			RT_TRACE(_module_rtl871x_security_c_, _drv_err_, ("%s: stainfo==NULL!!!\n",__func__));
 			res = _FAIL;
 		}
 	}