Fixing the unused variable compiler issue

- This commit would fix the error that are spotted by meson
  when werror=true is enforced.

  Tested By:

  - Compiled , and unit tests are passed.

Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
Change-Id: I330abdba69af36f8e02a1c22b76644beadb1c336
diff --git a/bmc_epoch.cpp b/bmc_epoch.cpp
index 9c8affc..7eeee32 100644
--- a/bmc_epoch.cpp
+++ b/bmc_epoch.cpp
@@ -98,8 +98,8 @@
     return value;
 }
 
-int BmcEpoch::onTimeChange(sd_event_source* es, int fd, uint32_t /* revents */,
-                           void* userdata)
+int BmcEpoch::onTimeChange(sd_event_source* /* es */, int fd,
+                           uint32_t /* revents */, void* /* userdata */)
 {
     std::array<char, 64> time{};