bpf: add raw_map_val_adj probe that tests dynamic map access
bpf: add raw_map_val_adj probe that tests dynamic map access

Add a probe for availability of dynamic map access. On success it
emits HAVE_MAP_VAL_ADJ into the bpf_features.h header that can be
used from BPF code.

Signed-off-by: Daniel Borkmann <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@cilium.io>

tklauser/cilium,gumpt/cilium,cilium/cilium,gumpt/cilium,tgraf/cilium,tgraf/cilium,tklauser/cilium,gumpt/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,scanf/cilium,scanf/cilium,scanf/cilium,eloycoto/cilium,tklauser/cilium,eloycoto/cilium,eloycoto/cilium,gumpt/cilium,mskarbek/cilium,scanf/cilium,michi-covalent/cilium,gumpt/cilium,eloycoto/cilium,gumpt/cilium,tklauser/cilium,mskarbek/cilium,michi-covalent/cilium,eloycoto/cilium,eloycoto/cilium,scanf/cilium,mskarbek/cilium,mskarbek/cilium,gumpt/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,mskarbek/cilium,cilium/cilium,scanf/cilium,eloycoto/cilium,mskarbek/cilium,scanf/cilium,tgraf/cilium,cilium-team/cilium