vibrator: fix log format and level issue

1.fix log format issue to improve readability
2.change log level to Slog.d

Example:
    old: "Stopping external vibrationExternalVibration..."
    new: "Stopping external vibration: ExternalVibration..."

Test: N/A

Change-Id: Id1e0f81e2db86107c7d5f6f7022700ea84176124
Signed-off-by: shenyanfeng <shenyanfeng@xiaomi.com>