staging: lustre: Use min3 macro

Replace comparsions between three expressions using
two min macros with min3 macro. Done using Coccinelle
Script:

@@
expression e1;
expression e2;
expression e3;
@@
(
- min(min(e1, e2), e3)
+ min3(e1, e2, e3)
|
- min(e1, min(e2, e3))
+ min3(e1, e2, e3)
)

Signed-off-by: Gargi Sharma <gs051095@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>