phy: dp83640: select CONFIG_CRC32

phy: dp83640: select CONFIG_CRC32

Without crc32, this driver fails to link:

arm-linux-gnueabi-ld: drivers/net/phy/dp83640.o: in function `match':
dp83640.c:(.text+0x476c): undefined reference to `crc32_le'

Fixes: fece27541b53 ("dp83640: Include hash in timestamp/packet matching")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>