android/benchmark: wait 60s by default after rebooting

Be more conservative and wait 60s (instead of 20) after each reboot to
be sure platform is stable.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
diff --git a/libs/utils/android/benchmark.py b/libs/utils/android/benchmark.py
index 429037e..ba51521 100644
--- a/libs/utils/android/benchmark.py
+++ b/libs/utils/android/benchmark.py
@@ -100,8 +100,8 @@
                 default=None,
                 help='Path of the Android boot.img to be used')
         parser.add_argument('--boot-timeout', type=int,
-                default=20,
-                help='Timeout in [s] to wait after a reboot (default 20)')
+                default=60,
+                help='Timeout in [s] to wait after a reboot (default 60)')
 
         # Android settings
         parser.add_argument('--android-device', type=str,