octeontx2-af: Modify rvu_reg_poll() to check reg atleast twice

Currently on the first check if the operation is still not
finished, the poll goes to sleep for 2-5 usecs. But if for
some reason (due to other priority stuff like interrupts etc) by
the time the poll wakes up the 10ms time is expired then we don't
check if operation is finished or not and return failure.

This patch modifies poll logic to check HW operation after sleep so
that the status is checked atleast twice.

Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>