Disable legacy 8259 PIC before enabling APIC

Reviewed-on: xt-sys/exectos#5
Reviewed-by: Rafal Kupiec <belliash@noreply.codingworkshop.git>
Co-authored-by: Jozef Nagy <schkwve@gmail.com>
Co-committed-by: Jozef Nagy <schkwve@gmail.com>

xtoskrnl/includes/hl.h

@@ -11,8 +11,11 @@
 
 #include <xtos.h>
 
-
 /* HAL library routines forward references */
+XTCDECL
+VOID
+HlDisablePic(VOID);
+
 XTAPI
 VOID
 HlClearScreen(VOID);