arch/arm64: configs: Enable basic tracing for IORap

Android 11's IORap prefetching service uses the following ftrace events
to profile I/O activity during app launches:

- mm_filemap_add_to_page_cache
- mm_filemap_delete_from_page_cache

Perfetto, the tracing daemon, is capable of using tracefs directly at
/sys/kernel/tracing, so we can forego debugfs and enable tracing by
itself now that tracefs' unnecessary dependency on debugfs has been
removed.

Signed-off-by: Danny Lin <[email protected]>
Signed-off-by: K A R T H I K <[email protected]>

arch/arm64/configs/vendor/violet-perf_defconfig

@@ -247,6 +247,10 @@ CONFIG_SLAB_FREELIST_RANDOM=y
 CONFIG_SLAB_FREELIST_HARDENED=y
 # CONFIG_SLUB_CPU_PARTIAL is not set
 # CONFIG_SYSTEM_DATA_VERIFICATION is not set
+CONFIG_FTRACE=y
+CONFIG_ENABLE_DEFAULT_TRACERS=y
+# CONFIG_UPROBE_EVENTS is not set
+# CONFIG_TRACING_EVENTS_GPIO is not set
 CONFIG_PROFILING=y
 CONFIG_TRACEPOINTS=y
 CONFIG_JUMP_LABEL=y