bpf: use BPF_CAST_CALL for casting bpf call

verifier.c uses BPF_CAST_CALL for casting bpf call except at one
place in jit_subprogs(). Let's use the macro for consistency.
Signed-off-by: NPrashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

kernel/bpf/verifier.c

@@ -7647,9 +7647,8 @@ static int jit_subprogs(struct bpf_verifier_env *env)
 			    insn->src_reg != BPF_PSEUDO_CALL)
 				continue;
 			subprog = insn->off;
-			insn->imm = (u64 (*)(u64, u64, u64, u64, u64))
-				func[subprog]->bpf_func -
-				__bpf_call_base;
+			insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) -
+				    __bpf_call_base;
 		}
 
 		/* we use the aux data to keep a list of the start addresses