mem-cache: Fix increasing replacement count

mem-cache: Fix increasing replacement count

Replacements should be increased when there is any evicted
block, which does not necessarily have to be the victim.

For example, assume a superblock contains 4 blocks, and both
A and C are stored compressed (belonging to SB_1). Then F,
from SB2 needs to make room by replacing SB1. If F map to
location 2, the number of replacements should be increased,
even though 2 had no valid blocks:

 Tag      Data          Tag     Data
|SB_1|--|A|X|C|X|  --> |SB_2| |X|F|X|X|
         1 2 3 4               1 2 3 4

Change-Id: I7b3735d28a35faa8d8fa613a1555bb258da65859
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18208
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>