LU-16438 llite: remove false outdated comment

LU-16438 llite: remove false outdated comment

Old commit 99727c7a1 from Lustre 2.6 changed
ll_i2gids() behavior without updating the function
documentation accordingly. Fix it as this is confusing.

Test-Parameters: trivial
Fixes: 99727c7 ("LU-4476 kernel: support process namespace containers")
Change-Id: Iccc50fe6ac9e02de9bae7fd8f91e3e73ff45e327
Signed-off-by: Aurelien Degremont <degremoa@amazon.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49539
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>