NVMEDevice: Remove the performance counter

NVMEDevice: Remove the performance counter

Compared with other approach (KernelDevice, iouring), it does not
have such feature, so remove it to simplify the code and improve
the performance. Because, each thread will call the logger and calculate
the time, it is very time consuming. And the upper layer in bluestore has
the feature to track each I/O task.

And it is not readable if we add ifdef configure to enable this feature,
so in my mind that I suggest removing this latency track. And the
latency benefit demonstrated by SPDK is already approved, so we do not
need to tracking every I/O time when invoking SPDK driver.

Signed-off-by: Ziye Yang <ziye.yang@intel.com>