meta-google: gbmc-ip-monitor: increase the start timeout

In some cases gbmc-ip-monitor failed to start within the default timeout
90s, this extend the timeout so that it has enough time to start.

Change-Id: I79e82f5110f72371019390a168c8b8be5f4d9750
Signed-off-by: Yuxiao Zhang <yuxiaozhang@google.com>
(cherry picked from commit c28937836f712db07267985b557eedf0924b09ae)

meta-google/recipes-google/networking/files/gbmc-ip-monitor.service

diff --git a/meta-google/recipes-google/networking/files/gbmc-ip-monitor.service b/meta-google/recipes-google/networking/files/gbmc-ip-monitor.service
index 435eac9..2681828 100644
--- a/meta-google/recipes-google/networking/files/gbmc-ip-monitor.service
+++ b/meta-google/recipes-google/networking/files/gbmc-ip-monitor.service
@@ -4,6 +4,7 @@
 [Service]
 Type=notify
 ExecStart=/usr/libexec/gbmc-ip-monitor.sh
+TimeoutStartSec=5min
 
 [Install]
 WantedBy=multi-user.target