Add support for ARMv9.3-A and ARMv9.4-A.

Bug: 364383722
Test: presubmit, internal build with the new arch variant
Change-Id: I151d7f5953cbec10e64887184a04d9121cde63e9
diff --git a/cc/config/arm64_device.go b/cc/config/arm64_device.go
index 45b1580..25edb79 100644
--- a/cc/config/arm64_device.go
+++ b/cc/config/arm64_device.go
@@ -53,6 +53,16 @@
 			"-mbranch-protection=standard",
 			"-fno-stack-protector",
 		},
+		"armv9-3a": []string{
+			"-march=armv9.3-a",
+			"-mbranch-protection=standard",
+			"-fno-stack-protector",
+		},
+		"armv9-4a": []string{
+			"-march=armv9.4-a",
+			"-mbranch-protection=standard",
+			"-fno-stack-protector",
+		},
 	}
 
 	arm64Ldflags = []string{