[SPARC]: sbus/vfc_i2c: remove sleep_on() usage

Use wait-queue directly instead of the deprecated sleep_on()
function. This required adding a local wait-queue. Also use new (added in
separate patch to K-J) usecs to jiffies function to convert value.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: David S. Miller <davem@davemloft.net>