mem-cache: count pf filtered by demand to the same cache line

Add a stat to count how many prefetch request are filtered in the
prefetch queue becasue a demand is going to the same cache line
Also adding a corresponding debug statement for when it happens

Change-Id: I52475f19bd109c135b7259d08d5f5c0b5fd90ee5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/47203
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
2 files changed