staging: lustre: Move assignments out of function calls.

Assignments inside of function calls confuse the reader and should be
avoided, so it was moved out before the call.

Found with Coccinelle, semantic patch:
@@
identifier f;
expression e1, e2;
assignment operator a;
@@

+ e1 a e2;
f(...,
- (e1 a e2)
+ e1
 ,...);

Signed-off-by: Elise Lennion <elise.lennion@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>