mem-cache: Add an extra decomp lat to multi compressor

mem-cache: Add an extra decomp lat to multi compressor

There is extra hardware required when dealing with multi
compressors. As such, add a parameter to allowing increasing
their decompression latency to account for any extra delay.

Change-Id: I153e4c5ab6927ac092e2ebd767fe88974597bb20
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33382
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>