mem-cache: Use block iteration in BaseSetAssoc

mem-cache: Use block iteration in BaseSetAssoc

Use block iteration instead of numSets and assoc in print(),
cleanupRefs() and computeStats().

This makes these functions rely solely on what they are used for:
printing and calculating stats of blocks. With the addition of
Sectors an extra indirection level is added, and thus these
functions would be skipping blocks.

Change-Id: I0006f82736cce02ba3e501ffafe9236f748daf32
Reviewed-on: https://gem5-review.googlesource.com/10143
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>