docs: update seccomp whitelist
docs: update seccomp whitelist

the 'modify_ldt' was listed as "blocked by default",
but was whitelisted in 13a9d4e8993997b2bf9be7e96a8d7978a73d0b9b

this updates the documentation to reflect this

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

TheBigBear/docker,TheBigBear/docker,TheBigBear/docker