time: Clean up CLOCK_MONOTONIC_RAW time handling

time: Clean up CLOCK_MONOTONIC_RAW time handling

Now that we fixed the sub-ns handling for CLOCK_MONOTONIC_RAW,
remove the duplicitive tk->raw_time.tv_nsec, which can be
stored in tk->tkr_raw.xtime_nsec (similarly to how its handled
for monotonic time).

Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Miroslav Lichvar <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Stephen Boyd <[email protected]>
Cc: Kevin Brodsky <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Daniel Mentz <[email protected]>
Tested-by: Daniel Mentz <[email protected]>
Signed-off-by: John Stultz <[email protected]>