Documentation typo fix in EVP_EncryptInit.pod

Remove duplicate declaration of `EVP_CIPHER_key_length` in the synopsis.

CLA: trivial

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5792)

doc/man3/EVP_EncryptInit.pod

diff --git a/doc/man3/EVP_EncryptInit.pod b/doc/man3/EVP_EncryptInit.pod
index 030b010..2e3a45a 100644
--- a/doc/man3/EVP_EncryptInit.pod
+++ b/doc/man3/EVP_EncryptInit.pod
@@ -99,7 +99,6 @@
 
  int EVP_CIPHER_nid(const EVP_CIPHER *e);
  int EVP_CIPHER_block_size(const EVP_CIPHER *e);
- int EVP_CIPHER_key_length(const EVP_CIPHER *e)
  int EVP_CIPHER_key_length(const EVP_CIPHER *e);
  int EVP_CIPHER_iv_length(const EVP_CIPHER *e);
  unsigned long EVP_CIPHER_flags(const EVP_CIPHER *e);