mem-ruby: Fix MultiGrainBloomFilter total count calculation

Previous value was always 0, and was never incrementing. The
total count should take into account the value stored in the
entry.

Change-Id: I93813e3f388198967b30cf11848a8a8c3a7b91f4
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18733
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

src/mem/ruby/filters/MultiGrainBloomFilter.cc

@@ -105,7 +105,7 @@ MultiGrainBloomFilter::getTotalCount()
     }
 
     for (int i=0; i < m_page_filter_size; ++i) {
-        count += m_page_filter[i] = 0;
+        count += m_page_filter[i];
     }
 
     return count;