i2c: smbus: add DDR support for SPD

On my x05 laptop I got:
Memory type 0x12 not supported yet, not instantiating SPD

Adding the 0x12 case lead to a successful instantiated SPD AT24 EEPROM.
i801_smbus 0000:00:1f.3: SMBus using polling
i2c i2c-6: 2/2 memory slots populated (from DMI)
at24 6-0050: 256 byte spd EEPROM, read-only
i2c i2c-6: Successfully instantiated SPD at 0x50
at24 6-0051: 256 byte spd EEPROM, read-only

And then, I decoded it successfully via decode-dimms.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/i2c-smbus.c

@@ -361,9 +361,15 @@ void i2c_register_spd(struct i2c_adapter *adap)
 		return;
 	}
 
+	/*
+	 * Memory types could be found at section 7.18.2 (Memory Device — Type), table 78
+	 * https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf
+	 */
 	switch (common_mem_type) {
+	case 0x12:	/* DDR */
 	case 0x13:	/* DDR2 */
 	case 0x18:	/* DDR3 */
+	case 0x1B:	/* LPDDR */
 	case 0x1C:	/* LPDDR2 */
 	case 0x1D:	/* LPDDR3 */
 		name = "spd";