cpu-o3: added _amo_op parameter in o3 LSQ

cpu-o3: added _amo_op parameter in o3 LSQ

Fix bug with AMO (or RMW) instructions where the amo_op variable
is not being propagated to the LSQ request.

Change-Id: I60c59641d9b497051376f638e27f3c4cc361f615
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19814
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>