arm64: dts: juno: Add cache-level property to L2 caches

arm64: dts: juno: Add cache-level property to L2 caches

Add the missing cache-level property to L2 caches. This is needed if
we need to find the last level cache directly from the device tree cache
node.

Link: https://lore.kernel.org/r/20220629095959.1115587-1-sudeep.holla@arm.com
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>