block: rsxx: select CONFIG_CRC32

Without crc32, the driver fails to link:

arm-linux-gnueabi-ld: drivers/block/rsxx/config.o: in function `rsxx_load_config':
config.c:(.text+0x124): undefined reference to `crc32_le'

Fixes: 8722ff8 ("block: IBM RamSan 70/80 device driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/Kconfig

@@ -445,6 +445,7 @@ config BLK_DEV_RBD
 config BLK_DEV_RSXX
  tristate "IBM Flash Adapter 900GB Full Height PCIe Device Driver"
  depends on PCI
+ select CRC32
  help
  Device driver for IBM's high speed PCIe SSD
  storage device: Flash Adapter 900GB Full Height.