staging: android: logger: clarify code in clock_interval

Add commentary, rename the function and make the code easier to read.

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: Ied44dd4184197a58e2c008bbaa212752f16799d6