Fix bpf_trace_printk() for big-endian targets

The format string for bpf_trace_printk() gets garbled during the
conversion of the LLVM IR code to the corresponding BPF object.
This happens because bcc explicitly sets the data layout of the
module to 'e-m:e-p:64:64-i64:64-n32:64-S128' which is valid for
little-endian targets only. If the arch is set to 'bpf', LLVM
selects the correct data layout automatically and there is no
need to set this explicitly.
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Fixes: #1723

src/cc/bpf_module.cc

@@ -615,7 +615,6 @@ int BPFModule::finalize() {
   std::map<std::string, std::tuple<uint8_t *, uintptr_t>> tmp_sections,
       *sections_p;
 
-  mod->setDataLayout("e-m:e-p:64:64-i64:64-n32:64-S128");
   mod->setTargetTriple("bpf-pc-linux");
   sections_p = rw_engine_enabled_ ? &sections_ : &tmp_sections;