i2c/eeprom: Recognize VGN as a valid Sony Vaio name prefix

Recent (i.e. 2005 and later) Sony Vaio laptops have names beginning
with VGN rather than PCG. Update the eeprom driver so that it
recognizes these.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/chips/eeprom.c

@@ -204,12 +204,16 @@ static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
 		goto exit_kfree;
 
 	/* Detect the Vaio nature of EEPROMs.
-	   We use the "PCG-" prefix as the signature. */
+	   We use the "PCG-" or "VGN-" prefix as the signature. */
 	if (address == 0x57) {
-		if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
-		 && i2c_smbus_read_byte(new_client) == 'C'
-		 && i2c_smbus_read_byte(new_client) == 'G'
-		 && i2c_smbus_read_byte(new_client) == '-') {
+		char name[4];
+
+		name[0] = i2c_smbus_read_byte_data(new_client, 0x80);
+		name[1] = i2c_smbus_read_byte(new_client);
+		name[2] = i2c_smbus_read_byte(new_client);
+		name[3] = i2c_smbus_read_byte(new_client);
+
+		if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
 			dev_info(&new_client->dev, "Vaio EEPROM detected, "
 				 "enabling privacy protection\n");
 			data->nature = VAIO;