arc: Increase ARC boot timeout.

On some slow devices, ARC does not boot within 60 seconds.

BUG=chromium:865213
TEST=tast -verbose run DUT arc.Boot

Change-Id: I8d98b0db9e135ffcf3278684fc6a6cd543fe48e9
Reviewed-on: https://chromium-review.googlesource.com/1143123
Commit-Ready: Shuhei Takahashi <[email protected]>
Tested-by: Shuhei Takahashi <[email protected]>
Reviewed-by: Dan Erat <[email protected]>
diff --git a/src/chromiumos/tast/local/arc/boot_phase.go b/src/chromiumos/tast/local/arc/boot_phase.go
index 5e6ed74..3ebccb3 100644
--- a/src/chromiumos/tast/local/arc/boot_phase.go
+++ b/src/chromiumos/tast/local/arc/boot_phase.go
@@ -20,7 +20,7 @@
 )
 
 const (
-	bootTimeout         = 60 * time.Second
+	bootTimeout         = 90 * time.Second
 	intentHelperTimeout = 20 * time.Second
 
 	logcatName = "logcat.txt"