ci: Skip riscv64 for bpf

There is a missing pt_regs implementation in args.rs

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>

.github/workflows/build-aya-bpf.yml

@@ -21,7 +21,8 @@ jobs:
           - x86_64
           - aarch64
           - arm
-          - riscv64
+          # Disable riscv64 due to missing pt_regs handling in aya-bpf/args.rs
+          # - riscv64
     runs-on: ubuntu-20.04
 
     steps: