mem-cache: Create block insertion function

mem-cache: Create block insertion function

Create a block insertion function to be used when inserting
blocks. This resets the number of references to 1 (the
insertion is taken into account), sets the insertion tick,
and set secure state.

Change-Id: Ifc34cbbd1c125207ce47912d188809221c7a157e
Reviewed-on: https://gem5-review.googlesource.com/9824
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>