staging: lustre: obdclass: Replace 'unsigned' with 'unsigned int'

Replace 'unsigned' with 'unsigned int' to improve readability.
Issues found with checkpatch.pl

Signed-off-by: Dafna Hirschfeld <dafna3@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>