Merge pull request #894 from Xilinx/errata-855873

zynqmp: Enable workaround for errata 855873

plat/xilinx/zynqmp/platform.mk

@@ -27,6 +27,7 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+override ERRATA_A53_855873 := 1
 override ENABLE_PLAT_COMPAT := 0
 override PROGRAMMABLE_RESET_ADDRESS := 1
 PSCI_EXTENDED_STATE_ID := 1