LU-15317 llite: Add FID to async ra iotrace

LU-15317 llite: Add FID to async ra iotrace

IOtrace log entries need to include the FID of the file
concerned.  Add this to async readahead.

test-parameters: trivial

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I8d788969f29412ce88f1cafa229977f6efa20962
Reviewed-on: https://review.whamcloud.com/45912
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>