staging: lustre: obdclass: Add 'const' to char* array

Replace 'const char*' arrays with 'const char * const'
since the values in the arrays are not changed.
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>