simplify sequence number processing

Newer GCC didn't like the complexity of the sequence calculation,
so simplify it.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I884a34e4317c2d33b33abf45687ae159f150f84b
diff --git a/ipmbbridged.cpp b/ipmbbridged.cpp
index 78b1c7f..678c750 100644
--- a/ipmbbridged.cpp
+++ b/ipmbbridged.cpp
@@ -316,11 +316,7 @@
 
     for (int i = 0; i < ipmbMaxOutstandingRequestsCount; i++)
     {
-        seqNum = ++seqNum & ipmbSeqMask;
-        if (seqNum == ipmbMaxOutstandingRequestsCount)
-        {
-            seqNum = 0;
-        }
+        seqNum = (seqNum + 1) % ipmbMaxOutstandingRequestsCount;
 
         if (outstandingRequests[seqNum] == nullptr)
         {