[warnings] remove some redundant declarations

Discovered with -Wredundant-decls

lib/minip/include/lib/minip.h

@@ -87,8 +87,6 @@ static inline status_t tcp_accept(tcp_socket_t *listen_socket, tcp_socket_t **ac
 
 /* utilities */
 void gen_random_mac_address(uint8_t *mac_addr);
-uint32_t minip_parse_ipaddr(const char *addr, size_t len);
-
 uint32_t minip_parse_ipaddr(const char *addr, size_t len);
 void printip(uint32_t x);
 void printip_named(const char *s, u32 x);