LU-17555 ptlrpc: removed unused lm_repsize accessors

LU-17555 ptlrpc: removed unused lm_repsize accessors

ptlrpc_req_get_repsize() and ptlrpc_req_set_repsize() are unused.

ptlrpc_req_set_repsize() is superseded by
ptlrpc_request_set_replen() so remove the unused variants.

Test-Parameters: trivial
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: Ib89a57c00605b110ec28040614aecba9826f5ffa
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54089
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>