mem: Remove unused variable

The variable *sys in dram_ctrl.cc was only used in an assert() check,
therefore it has been removed to allow building gem5.fast without
errors. A typo in a comment in abstract_mem.hh has also been corrected.

Change-Id: I2663545449ecfdb5a27c3574b79dd42beb4a49c8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21380
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
2 files changed