Revert "Disable BTI for now."

This reverts commit c75994d6235a023df6942fddeaa34b2a66f2e5f6.

Reason for revert: BTI shipped in S, and we're going to work on app compat outreach rather than regress this security feature.

Bug: https://issuetracker.google.com/216395195
Change-Id: Ic7143d756907ceb574a686258751840ce62c920f
diff --git a/cc/config/arm64_device.go b/cc/config/arm64_device.go
index 979c825..2d6bcb8 100644
--- a/cc/config/arm64_device.go
+++ b/cc/config/arm64_device.go
@@ -33,9 +33,7 @@
 		},
 		"armv8-a-branchprot": []string{
 			"-march=armv8-a",
-			// Disable BTI until drm vendors stop using OS libraries as sources
-			// of gadgets (https://issuetracker.google.com/216395195).
-			"-mbranch-protection=pac-ret",
+			"-mbranch-protection=standard",
 		},
 		"armv8-2a": []string{
 			"-march=armv8.2-a",