linux-phytec-fsl

libceph: make r_request msg_size calculation clearer

Although msg_size is calculated correctly, the terms are grouped in
a misleading way - snaps appears to not have room for a u32 length.
Move calculation closer to its use and regroup terms.

No functional change.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>