The type casting introduces an allocation, this will cause compiling failure when linking final bpf target.
So remove this casting to fix this issue.
BTW, the following is the failure I met:
= note: 07:24:12 [ERROR] fatal error: "unable to allocate function return #1"
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
Stack dump:
0. Running pass 'Function Pass Manager' on module 'trace_bpf-001a275b17e9eb12'.
1. Running pass 'BPF DAG->DAG Pattern Instruction Selection' on function '@_ZN7aya_bpf4maps11stack_trace10StackTrace11get_stackid17h32b649bc3780c0aaE'
Signed-off-by: Tw <wei.tan@intel.com>