ANDROID: KVM: arm64: make per-cpu trace file read-write

Userspace tools use the per-cpu trace file to clear the per-cpu trace
buffer, hence the should be able to open it for writing.

Bug: 428904926
Test: presubmit

Change-Id: Ie19fdf0a235745bff04b3a904b04950964b3497a
Signed-off-by: Nikita Ioffe <ioffe@google.com>

arch/arm64/kvm/hyp_trace.c

@@ -1044,7 +1044,7 @@ int hyp_trace_init_tracefs(void)
 		tracefs_create_file("trace_pipe_raw", TRACEFS_MODE_READ, per_cpu_dir,
 				    (void *)cpu, &hyp_trace_raw_fops);
 
-		tracefs_create_file("trace", TRACEFS_MODE_READ, per_cpu_dir,
+		tracefs_create_file("trace", TRACEFS_MODE_WRITE, per_cpu_dir,
 				    (void *)cpu, &hyp_trace_fops);
 	}