Set time variables only on timestamp messages

Upstream PR taligentx#339 (frankonski): call processTime() for 0xA5 and 0xEB
only when the message is an actual timestamp (panelData[6]/[7] == 0),
avoiding decoding time from non-timestamp panel data.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Konstantin Sinitsyn

src/dscKeybusProcessData.cpp

@@ -499,10 +499,9 @@ void dscKeybusInterface::processPanel_0x87() {
 void dscKeybusInterface::processPanel_0xA5() {
   if (!validCRC()) return;
 
-  processTime(2);
-
   // Timestamp
   if (panelData[6] == 0 && panelData[7] == 0) {
+    processTime(2);
     statusChanged = true;
     timestampChanged = true;
     return;
@@ -579,7 +578,13 @@ void dscKeybusInterface::processPanel_0xEB() {
   if (!validCRC()) return;
   if (dscPartitions < 3) return;
 
-  processTime(3);
+  // Timestamp
+  if (panelData[6] == 0 && panelData[7] == 0) {
+    processTime(3);
+    statusChanged = true;
+    timestampChanged = true;
+    return;
+  }
 
   byte partition;
   switch (panelData[2]) {