vdebug: Fix socket comparison warning on Windows

On GCC version 13.2,
the previous code emitted the following warning on Windows:

openocd/src/jtag/drivers/vdebug.c:254:19: warning: comparison of integer expressions of different signedness: 'int' and 'long long unsigned int' [-Wsign-compare]
  254 |         if (hsock == INVALID_SOCKET)

This patch fixes it and brings it in line with other socket handling code.

Change-Id: I7e05f83c6905cfaf66b68e8988c783e80cee4a48
Signed-off-by: Marek Vrbka <[email protected]>
Reviewed-on: https://review.openocd.org/c/openocd/+/8717
Tested-by: jenkins
Reviewed-by: Jan Matyas <[email protected]>
Reviewed-by: Jacek Wuwer <[email protected]>
Reviewed-by: Antonio Borneo <[email protected]>
Reviewed-by: R. Diez <[email protected]>

src/jtag/drivers/vdebug.c

@@ -252,7 +252,7 @@ static int vdebug_socket_open(char *server_addr, uint32_t port)
 
 #ifdef _WIN32
 	hsock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
-	if (hsock == INVALID_SOCKET)
+	if (hsock < 0)
 		rc = vdebug_socket_error();
 #elif defined __CYGWIN__
 	/* SO_RCVLOWAT unsupported on CYGWIN */