phosphor-ipmi-host: Set event msg buffer flag to hardcode to 0x0

Though event message buffer is not supported for 5.10 kernel request
the BMC is set to return msg buffer is hardcoded to return full 0x2;
instead of 0x0.

Signed-off-by: XP Chen <xiao-peng.chen@fii-na.com>
Change-Id: I92674dbdb54546653ff2b18574f3d8dfa21ae43f
diff --git a/systemintfcmds.cpp b/systemintfcmds.cpp
index 689b465..fe671a2 100644
--- a/systemintfcmds.cpp
+++ b/systemintfcmds.cpp
@@ -58,7 +58,7 @@
 
 //---------------------------------------------------------------------
 // Called by Host on seeing a SMS_ATN bit set. Return a hardcoded
-// value of 0x2 indicating we need Host read some data.
+// value of 0x0 to indicate Event Message Buffer is not supported
 //-------------------------------------------------------------------
 ipmi::RspType<uint8_t> ipmiAppGetMessageFlags()
 {
@@ -68,8 +68,8 @@
     // or when the Event Message buffer is disabled.
     // This path is used to communicate messages to the host
     // from within the phosphor::host::command::Manager
-    constexpr uint8_t setEventMsgBufferFull = 0x2;
-    return ipmi::responseSuccess(setEventMsgBufferFull);
+    constexpr uint8_t setEventMsgBufferNotSupported = 0x0;
+    return ipmi::responseSuccess(setEventMsgBufferNotSupported);
 }
 
 ipmi::RspType<bool,    // Receive Message Queue Interrupt Enabled