sparc: leon: Fix a retry loop in leon_init_timers()

The original code causes a static checker warning because it has a
continue inside a do { } while (0); loop.  In that context, a continue
and a break are equivalent.  The intent was to go back to the start of
the loop so the continue was a bug.

I've added a retry label at the start and changed the continue to a goto
retry.  Then I removed the do { } while (0) loop and pulled the code in
one indent level.

Fixes: 2791c1a4

 ("SPARC/LEON: added support for selecting Timer Core and Timer within core")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>