cfg80211: select CONFIG_CRC32

Without crc32 support, this fails to link:

arm-linux-gnueabi-ld: net/wireless/scan.o: in function `cfg80211_scan_6ghz':
scan.c:(.text+0x928): undefined reference to `crc32_le'

Fixes: c8cb5b85

 ("nl80211/cfg80211: support 6 GHz scanning")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>