bpf: support BPF_F_NO_PREALLOC in bpf_map_def.h

Kernel requires maps of type BPF_MAP_TYPE_LPM_TRIE to not be
preallocated, so default enable the flag for these.

But even for non LPM_TRIE maps allow a negative num_entries
value to ask for 'non preallocated' maps.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I48d5d5813628c87094c5efa7266b0354b135dd7e
2 files changed