libbpf: Fix map creation flags sanitization

As BPF_F_MMAPABLE flag is now conditionnaly set (by map_is_mmapable),
it should not be toggled but disabled if not supported by kernel.

Fixes: 4fcac46c ("libbpf: only add BPF_F_MMAPABLE flag for data maps with global vars")
Signed-off-by: Ludovic L'Hours <ludovic.lhours@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230108182018.24433-1-ludovic.lhours@gmail.com


Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>