[CAD QSPI v1] spi: cadence-qspi: Add disable STIG mode quikrs.

[Ng, Boon Khai]

Hi Tom, Jagan

I hope you're doing well. I just wanted to follow up on the patch 
I submitted for review some time ago. I understand you're likely 
busy, but I would really appreciate it if you could take a look 
when you get a chance.

If there's anything you need from my side to facilitate
 the review process, feel free to let me know.

Thank you in advance for your time and assistance!

Regards,
Boon Khai