bpf: Refactor buffer allocation and simplify
bpf: Refactor buffer allocation and simplify

Golang's wrapper around the standard C malloc implementation ensures
that allocations are non-NULL, otherwise the application will crash:

  https://golang.org/cmd/cgo/

Skip the checks and error handling around C allocations, and refactor
to simplify upcoming patches.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@covalent.io>

scanf/cilium,tklauser/cilium,michi-covalent/cilium,scanf/cilium,tklauser/cilium,cilium/cilium,scanf/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,cilium-team/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium,scanf/cilium,tgraf/cilium,scanf/cilium,cilium/cilium,cilium-team/cilium,michi-covalent/cilium,scanf/cilium,cilium/cilium,scanf/cilium