samples: net: gptp: native_posix: Set 1ms clock accuracy

Instead of unknown clock accuracy, set it to 1ms for native_posix
boards. This looks better in TSN monitor.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
diff --git a/samples/net/gptp/boards/native_posix.conf b/samples/net/gptp/boards/native_posix.conf
index d0d3b87..c514520 100644
--- a/samples/net/gptp/boards/native_posix.conf
+++ b/samples/net/gptp/boards/native_posix.conf
@@ -3,3 +3,6 @@
 
 #CONFIG_ETH_NATIVE_POSIX_RANDOM_MAC=y
 CONFIG_ETH_NATIVE_POSIX_MAC_ADDR="00:00:5e:00:53:2a"
+
+# Assume 1 ms accuracy for native_posix simulated clock
+CONFIG_NET_GPTP_CLOCK_ACCURACY_1MS=y
diff --git a/samples/net/gptp/boards/native_posix_64.conf b/samples/net/gptp/boards/native_posix_64.conf
index d0d3b87..c514520 100644
--- a/samples/net/gptp/boards/native_posix_64.conf
+++ b/samples/net/gptp/boards/native_posix_64.conf
@@ -3,3 +3,6 @@
 
 #CONFIG_ETH_NATIVE_POSIX_RANDOM_MAC=y
 CONFIG_ETH_NATIVE_POSIX_MAC_ADDR="00:00:5e:00:53:2a"
+
+# Assume 1 ms accuracy for native_posix simulated clock
+CONFIG_NET_GPTP_CLOCK_ACCURACY_1MS=y