ptp: ocp: Use DIV64_U64_ROUND_UP for rounding.

The initial code used roundup() to round the starting time to
a multiple of a period.  This generated an error on 32-bit
systems, so was replaced with DIV_ROUND_UP_ULL().

However, this truncates to 32-bits on a 64-bit system.  Replace
with DIV64_U64_ROUND_UP() instead.

Fixes: b325af3c ("ptp: ocp: Add signal generators and update sysfs nodes")
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/r/20220506223739.1930-2-jonathan.lemon@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/ptp/ptp_ocp.c

@@ -1557,7 +1557,7 @@ ptp_ocp_signal_set(struct ptp_ocp *bp, int gen, struct ptp_ocp_signal *s)
 	start_ns = ktime_set(ts.tv_sec, ts.tv_nsec) + NSEC_PER_MSEC;
 	if (!s->start) {
 		/* roundup() does not work on 32-bit systems */
-		s->start = DIV_ROUND_UP_ULL(start_ns, s->period);
+		s->start = DIV64_U64_ROUND_UP(start_ns, s->period);
 		s->start = ktime_add(s->start, s->phase);
 	}