You don’t configure the WLC to discover the AP, the AP needs to discover the WLC. Here is a link to read: https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/70333-lap-registration.html
Now if disabling CDP prevents your AP from negotiating PoE, then you might need to enable CDP. So make sure your AP boots and negotiates PoE properly by connecting via console and looking at the output. The output will tell you a lot of things including the WLC discovery.
-Scott
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