mmc: reset: Clear the HMC-managed bios attr

Set the pvm_hmc_managed bios attribute to Disabled during a factory
reset to clear the indicator that says the system is HMC managed since a
factory reset is expected to remove the HMC information. The reset
function is already deleting the HMC save area directory created by
bmcweb.

Tested: Set the pvm_hmc_managed attribute to Enabled, then verified that
after a bios factory reset it's set to Disabled.

Change-Id: I2cbe9baaebb4a11b612f0940ff2a994a8474d3d6
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/utils.hpp b/utils.hpp
index acb44ca..8ff2370 100644
--- a/utils.hpp
+++ b/utils.hpp
@@ -45,6 +45,13 @@
  */
 void hiomapdResume(sdbusplus::bus::bus& bus);
 
+/** @brief Set the Hardware Management Console Managed bios attribute to
+ *         Disabled to clear the indication that the system is HMC-managed.
+ *
+ * @param[in] bus - The D-Bus bus object.
+ */
+void clearHMCManaged(sdbusplus::bus::bus& bus);
+
 } // namespace utils
 
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