Staging: rtlwifi: Replace return type

Replace return type and remove the respective assignment.

Issue found by Coccinelle.
Signed-off-by: Madhumitha Prabakaran <madhumithabiw@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtlwifi/core.c

@@ -377,9 +377,7 @@ static u16 _calculate_wol_pattern_crc(u8 *pattern, u16 len)
 	for (i = 0; i < len; i++)
 		crc = crc16_ccitt(pattern[i], crc);
 
-	crc = ~crc;
-
-	return crc;
+	return ~crc;
 }
 
 static void _rtl_add_wowlan_patterns(struct ieee80211_hw *hw,