[PATCH] ptp: ocp: select CRC16 to fix build error

ptp_ocp.c uses crc16(), so it should select CRC16 to
prevent a build error:

ERROR: modpost: "crc16" [drivers/ptp/ptp_ocp.ko] undefined!

Fixes: 3c3673bde50c ("ptp: ocp: Add firmware header checks")
Reported-by: kernel test robot <redacted>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vadim Fedorenko <redacted>
Cc: Jonathan Lemon <redacted>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <redacted>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
---
 drivers/ptp/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig

@@ -176,6 +176,7 @@ config PTP_1588_CLOCK_OCP
 	depends on !S390
 	depends on COMMON_CLK
 	select NET_DEVLINK
+	select CRC16
 	help
 	  This driver adds support for an OpenCompute time card.