ethtool: Add SFF-8436 and SFF-8636 max EEPROM length definitions

Added max EEPROM length defines for ethtool usage:
 #define ETH_MODULE_SFF_8636_MAX_LEN     640
 #define ETH_MODULE_SFF_8436_MAX_LEN     640

These definitions are used to determine the EEPROM
data length when reading high eeprom pages.

For example, SFF-8636 EEPROM data from page 03h
needs to be stored at data[512] - data[639].
Signed-off-by: Erez Alfasi <ereza@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

include/uapi/linux/ethtool.h

@@ -1712,6 +1712,9 @@ static inline int ethtool_validate_duplex(__u8 duplex)
 #define ETH_MODULE_SFF_8436		0x4
 #define ETH_MODULE_SFF_8436_LEN		256
 
+#define ETH_MODULE_SFF_8636_MAX_LEN     640
+#define ETH_MODULE_SFF_8436_MAX_LEN     640
+
 /* Reset flags */
 /* The reset() operation must clear the flags for the components which
  * were actually reset.  On successful return, the flags indicate the