feat(serial): call set_baud_rate in main

k/k.c

@@ -35,6 +35,7 @@ void k_main(unsigned long magic, multiboot_info_t *info)
     char star[4] = "|/-\\";
     char *fb = (void *)0xb8000;
 
+    set_baud_rate();
     init_serial();
 
     printf("bonjour\r\n");

k/serial.h

@@ -20,6 +20,7 @@
 
 #define EMPTY_TRANSMITTER (0x1 << 5)
 
+void set_baud_rate(void);
 void init_serial(void);
 int write(const char *buf, size_t count);