misc: match declaration and definition signatures

[badochov]

JIRA: RTOS-927

Warnings fixed:

 /github/workspace/phoenix-rtos-lwip/lib-lwip/src/api/api_msg.c: In function 'lwip_netconn_do_send':
Warning: /github/workspace/phoenix-rtos-lwip/lib-lwip/src/api/api_msg.c:1598:44: warning: the comparison will always evaluate as 'true' for the address of 'netpacket_hwaddr' will never be NULL [-Waddress]
 1598 |           if (msg->msg.b->netpacket_hwaddr != NULL && msg->msg.b->netpacket_hwaddr_len != 0) {
      |                                            ^~
In file included from lib-lwip/src/include/lwip/api.h:47,
                 from lib-lwip/src/include/lwip/priv/api_msg.h:47,
                 from /github/workspace/phoenix-rtos-lwip/lib-lwip/src/api/api_msg.c:43:
lib-lwip/src/include/lwip/netbuf.h:73:8: note: 'netpacket_hwaddr' declared here
   73 |   u8_t netpacket_hwaddr[ETH_HWADDR_LEN];
      |        ^~~~~~~~~~~~~~~~

 Warning: /github/workspace/phoenix-rtos-lwip/lib-lwip/src/netif/ppp/chap_ms.c:497:32: warning: argument 2 of type 'const u_char[16]' {aka 'const unsigned char[16]'} with mismatched bound [-Warray-parameter=]
497 |                   const u_char PasswordHash[MD4_SIGNATURE_SIZE],
    |                   ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/github/workspace/phoenix-rtos-lwip/lib-lwip/src/netif/ppp/chap_ms.c:155:52: note: previously declared as 'const u_char *' {aka 'const unsigned char *'}
155 | static void     ChallengeResponse (const u_char *, const u_char *, u_char[24]);
    |                                                    ^~~~~~~~~~~~~~
Warning: /github/workspace/phoenix-rtos-lwip/lib-lwip/src/netif/ppp/chap_ms.c:875:16: warning: argument 8 of type 'u_char[]' {aka 'unsigned char[]'} with mismatched bound [-Warray-parameter=]
875 |         u_char authResponse[], int authenticator) {
    |         ~~~~~~~^~~~~~~~~~~~~~
/github/workspace/phoenix-rtos-lwip/lib-lwip/src/netif/ppp/chap_ms.c:179:29: note: previously declared as 'u_char[41]' {aka 'unsigned char[41]'}
179 |                   u_char *, u_char[MS_AUTH_RESPONSE_LENGTH+1], int);