Cpu: Convert `Step` default value to maxint

https://gerrit.openbmc.org/c/openbmc/bmcweb/+/57143/3/redfish-core/lib/processor.hpp
makes the bmcweb ignore `Step` if its value is default (0 in this case).
For a new processor, it's possible that the stepping is really `0`. In
this case, the `Step` will still be ignored which is not expected.
Changing its default to maxint can avoid this issue.

Change-Id: I0e40c65c943f1deb62b8d81f4b5259385af06700
Signed-off-by: Michael Shen <gpgpgp@google.com>
diff --git a/yaml/xyz/openbmc_project/Inventory/Item/Cpu.interface.yaml b/yaml/xyz/openbmc_project/Inventory/Item/Cpu.interface.yaml
index 7b81528..8b3fb6f 100644
--- a/yaml/xyz/openbmc_project/Inventory/Item/Cpu.interface.yaml
+++ b/yaml/xyz/openbmc_project/Inventory/Item/Cpu.interface.yaml
@@ -55,7 +55,7 @@
       type: uint16
       description: >
           The step value for this processor
-      default: 0
+      default: maxint
     - name: Microcode
       type: uint32
       description: >