arm: zynq: Invalidate L1 in secondary boot

arm: zynq: Invalidate L1 in secondary boot

With an implementation of cpu_kill() (commit fda2191, 'zynq: Add support
for zynq_cpu_kill function') the killed core's L1 is not guaranteed to
be properly flushed when going into suspend. Also, during boot, Linux
initiates a clean-invalidate operation only, resulting in faulty data to
be written to the memory system during resume.
Therefore invalidate the L1 in the secondary boot path to avoid these
issues.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>