crypto: lib/curve25519 - Move selftest prototype into header file

This patch moves the curve25519_selftest into curve25519.h so
we don't get a warning from gcc complaining about a missing
prototype.
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

include/crypto/curve25519.h

@@ -28,6 +28,8 @@ void curve25519_arch(u8 out[CURVE25519_KEY_SIZE],
 void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],
 			  const u8 secret[CURVE25519_KEY_SIZE]);
 
+bool curve25519_selftest(void);
+
 static inline
 bool __must_check curve25519(u8 mypublic[CURVE25519_KEY_SIZE],
 			     const u8 secret[CURVE25519_KEY_SIZE],

lib/crypto/curve25519.c

@@ -13,8 +13,6 @@
 #include <linux/module.h>
 #include <linux/init.h>
 
-bool curve25519_selftest(void);
-
 static int __init mod_init(void)
 {
 	if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS) &&