ethtool 5.2 qsfp.c heap buffer overflow

Hi,

The function "sff8636_dom_parse", called from "sff8636_show_dom",
disregards the module eeprom size returned from the driver and assumes
the existence of upper pages, e.g.

sd->sfp_temp[HALRM] = SFF8636_OFFSET_TO_TEMP(SFF8636_TEMP_HALRM);

To reproduce: return ETH_MODULE_SFF_8636_LEN (256) for module eeprom
length in NIC driver, compile ethtool 5.2 with clang and address
sanitizer linked in, run ethtool -m.

Best regards,
Dave