crc-t10dif: Allow current transform to be inspected in sysfs

Add a way to print the currently active CRC algorithm in:

	/sys/module/crc_t10dif/parameters/transform

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>