examples/cmb-p2p: fix the p2p example #368

Job	Run time
basic sanity build	40s
nix build	39s
compiler builds (gcc)	9s
run emulated nvme device tests (fedora, 38, default)	30s
compiler builds (clang)	8s
distribution builds (almalinux, 8)	37s
run emulated nvme device tests (fedora, rawhide, iommufd)	34s
distribution builds (almalinux, 9)	35s
distribution builds (alpine, latest)	15s
run scan-build	1m 39s
run sparse	49s
distribution builds (archlinux, latest)	27s
distribution builds (debian, trixie)	32s
distribution builds (debian, bookworm)	32s
distribution builds (debian, bullseye)	33s
distribution builds (debian, buster)	47s
distribution builds (fedora, rawhide)	32s
distribution builds (fedora, 38)	54s
distribution builds (fedora, 37)	1m 6s
distribution builds (rockylinux, 8)	38s
distribution builds (rockylinux, 9)	47s
distribution builds (ubuntu, mantic)	27s
distribution builds (ubuntu, lunar)	32s
distribution builds (ubuntu, jammy)	31s
distribution builds (ubuntu, focal)	33s
	15m 26s

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