bpf: crypto: Use the correct destructor kfunc type

In the Linux kernel, the following vulnerability has been resolved:

bpf: crypto: Use the correct destructor kfunc type

With CONFIG_CFI enabled, the kernel strictly enforces that indirect

function calls use a function pointer type that matches the target

function. I ran into the following type mismatch when running BPF

self-tests:

CFI failure at bpf_obj_free_fields+0x190/0x238 (target:

bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc)

Internal error: Oops - CFI: 00000000f2008228 [#1] SMP

...

As bpf_crypto_ctx_release() is also used in BPF programs and using

a void pointer as the argument would make the verifier unhappy, add

a simple stub function with the correct type and register it as the

destructor kfunc instead.