Hi jjang,
May I know are you planning to use the Active Serial configuration scheme or Passive Serial configuration scheme with the Cyclone III device? Please refer to the attached document that you provide from Micron. As you can observe from the table did mention they validate the MT25Q for Passive Serial configuration scheme for Cyclone III using PFL IP in CPLD device. Thus you can still use the PFL IP v18.1 (in CPLD such as MAX V or MAX II) with MT25Q device to configure the Cyclone III via Passive Serial configuration scheme.
This KDB only reflect the MT25Q support for Active Serial configuration scheme in the Intel Quartus Prime software version 17.1 and later.
https://www.intel.com/content/www/us/en/programmable/support/support-resources/knowledge-base/component/2018/how-do-i-enable-micron-s-mt25q-support-for-eol-of-epcq---256mb--.html
For Cyclone III and older mature devices available in Quartus II v13.1, please use EPCQ-A flash device for Active Serial configuration support. You can refer to the following KDB for the patch to enable the EPCQ-A flash device support into Quartus II v13.1.
https://www.intel.com/content/altera-www/global/en_us/index/support/support-resources/knowledge-base/component/2018/-is-the-epcq-a-configuration-family-device-supported-in-any-of-t.html
Regards,
Nooraini