fix some compiler warnings

cpu/pic.c

@@ -2,8 +2,6 @@
 #include "cpu/io.h"
 
 void pic_remap(uint8_t offset1, uint8_t offset2) {
-    uint8_t a1, a2;
- 
     outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4);  // starts the initialization sequence (in cascade mode)
     io_wait();
     outb(PIC2_COMMAND, ICW1_INIT | ICW1_ICW4);

ps2/keyboard.c

@@ -5,6 +5,7 @@
 #include "cpu/pic.h"
 #include "cpu/idt.h"
 #include "cpu/io.h"
+#include "gfx/terminal.h"
 
 const char us_map[128] = {
     0, 27, '1', '2', '3', '4', '5', '6', '7', '8',
@@ -47,7 +48,7 @@ const char us_map[128] = {
 
 __attribute__((interrupt))
 static void irq(struct interrupt_descriptor_32 *frame) {
-    char scancode = inb(0x60);
+    uint8_t scancode = inb(0x60);
 
     if (scancode & 128) {
         goto end; // ignore release scancode