[SPARC]: sbus/aurora: replace schedule_timeout() with msleep_interruptible()

Use msleep_interruptible() instead of
schedule_timeout() to guarantee the task delays as expected.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Maximilian Attems <janitor@sternwelten.at>
Signed-off-by: Domen Puncer <domen@coderock.org>