cadence_gem: Make the revision a property

Expose the Cadence GEM revision as a property.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 541324373cf87b50f8be0439a0cb89f5028b016f.1491947224.git.alistair.francis@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/include/hw/net/cadence_gem.h b/include/hw/net/cadence_gem.h
index c469ffe..35de622 100644
--- a/include/hw/net/cadence_gem.h
+++ b/include/hw/net/cadence_gem.h
@@ -50,6 +50,7 @@
     uint8_t num_priority_queues;
     uint8_t num_type1_screeners;
     uint8_t num_type2_screeners;
+    uint32_t revision;
 
     /* GEM registers backing store */
     uint32_t regs[CADENCE_GEM_MAXREG];