mem-cache: Make (de)compression latencies params

mem-cache: Make (de)compression latencies params

Add 4 params to calculate compression and decompression latencies.
A pair of params informs how many chunks are parsed per cycle, and
the other pair informs how many extra cycles are needed after the
chunks are parsed to finish the (de)compression.

Change-Id: Ie67b0c298f06a08011f553789e3a9a1d89dd7c4f
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/36497
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>