Config: Fix a typo in the se.py script for setting fastmem
Config: Fix a typo in the se.py script for setting fastmem

This patch changes a hardcoded index 0 to the appropriate CPU index so
that fastmem is set correctly for all the CPUs in the system.

andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin