blockjob: remove clock argument from block_job_sleep_ns

blockjob: remove clock argument from block_job_sleep_ns

All callers are using QEMU_CLOCK_REALTIME, and it will not be possible to
support more than one clock when block_job_sleep_ns switches to a single
timer stored in the BlockJob struct.

Signed-off-by: Paolo Bonzini <[email protected]>
Reviewed-by: Alberto Garcia <[email protected]>
Tested-By: Jeff Cody <[email protected]>
Reviewed-by: Fam Zheng <[email protected]>
Reviewed-by: Jeff Cody <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>