crypto: ecc - make ecc into separate module

ecc.c have algorithms that could be used togeter by ecdh and ecrdsa.
Make it separate module. Add CRYPTO_ECC into Kconfig. EXPORT_SYMBOL and
document to what seems appropriate. Move structs ecc_point and ecc_curve
from ecc_curve_defs.h into ecc.h.

No code changes.

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index f328026..ecb697b 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -248,8 +248,12 @@
 	help
 	  Generic implementation of the Diffie-Hellman algorithm.
 
+config CRYPTO_ECC
+	tristate
+
 config CRYPTO_ECDH
 	tristate "ECDH algorithm"
+	select CRYPTO_ECC
 	select CRYPTO_KPP
 	select CRYPTO_RNG_DEFAULT
 	help