audio: update mOldTs.tv_nsec when mSleepNs > 0.

If the write of the hal layer returns quickly, there will be two consecutive writes, and insufficient data will cause noise. Because currently only the time when the current data is written is compared with the time when the data was last written.

Bug: 395756049

Change-Id: I47b2da33366cb597a65943fdcde58c641c31ea55
Signed-off-by: chenxin20 <chenxin20@xiaomi.com>