There are some options
[option 1]
revert the parisc bit of 23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3
This will restore the functionality you may want, but
as I said above, Kconfig is doing pointless things.
[option 2]
Stop using cc-cross-prefix, and pass CROSS_COMPILE explicitly.
This is what many architectures including arm, arm64 do.
You need to explicitly pass CROSS_COMPILE=aarch64-linux-gnu- etc.
if you are cross-compiling arm64.
[option 3]
Introduce ARCH=parisc64.
When you are building 64-bit kernel, you can pass ARCH=parisc64
A patch attached. (but not tested much)