Logging: IPMI: Add Clear method

Add the Clear method to xyz.openbmc_project.Logging.IPMI interface
to support clearing the IPMI SEL in phosphor-sel-logger. This method
does not have any arguments or return.

Signed-off-by: Charles Boyer <Charles.Boyer@fii-usa.com>
Change-Id: Ib4e4c178ee06cf17c0dc0e789e57483b96e2f436
diff --git a/yaml/xyz/openbmc_project/Logging/IPMI.interface.yaml b/yaml/xyz/openbmc_project/Logging/IPMI.interface.yaml
index 2b2e393..8c2ff14 100644
--- a/yaml/xyz/openbmc_project/Logging/IPMI.interface.yaml
+++ b/yaml/xyz/openbmc_project/Logging/IPMI.interface.yaml
@@ -75,3 +75,7 @@
       errors:
         - xyz.openbmc_project.Common.Error.InternalFailure
         - xyz.openbmc_project.Common.Error.InvalidArgument
+
+    - name: Clear
+      description: >
+        Clear the SEL entries from their storage location.