Revert "pldm: use std::expected for instance ID allocation"

This reverts commit 70262ed7bf854b25d4b65628bc3c892ddfe9380f.

Change-Id: I1f54d6b60bf3cfa9f00764140eec6167e1e182d6
Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
diff --git a/softoff/softoff.cpp b/softoff/softoff.cpp
index d72af59..9721c7e 100644
--- a/softoff/softoff.cpp
+++ b/softoff/softoff.cpp
@@ -271,6 +271,7 @@
 {
     constexpr uint8_t effecterCount = 1;
     PldmTransport pldmTransport{};
+    uint8_t instanceID;
     uint8_t mctpEID;
 
     mctpEID = pldm::utils::readHostEID();
@@ -284,13 +285,7 @@
     auto request = new (requestMsg.data()) pldm_msg;
     set_effecter_state_field stateField{
         PLDM_REQUEST_SET, PLDM_SW_TERM_GRACEFUL_SHUTDOWN_REQUESTED};
-    auto instanceIdResult =
-        pldm::utils::getInstanceId(instanceIdDb.next(pldmTID));
-    if (!instanceIdResult)
-    {
-        return PLDM_ERROR;
-    }
-    auto instanceID = instanceIdResult.value();
+    instanceID = instanceIdDb.next(pldmTID);
     auto rc = encode_set_state_effecter_states_req(
         instanceID, effecterID, effecterCount, &stateField, request);
     if (rc != PLDM_SUCCESS)