libcrc32c: Select CRYPTO in Kconfig

Selecting CRYPTO_CRC32C is not enough as CRYPTO which CRYPTO_CRC32C
depends on may be disabled.  This patch adds the select on CRYPTO.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/lib/Kconfig b/lib/Kconfig
index ce303f1..fd4118e 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -64,6 +64,7 @@
 
 config LIBCRC32C
 	tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
+	select CRYPTO
 	select CRYPTO_CRC32C
 	help
 	  This option is provided for the case where no in-kernel-tree