Remove malloc, pursue a more DOS-like MM approach

kernel/main.asm

@@ -73,15 +73,11 @@ start:
   xor ax, ax
   mov ds, ax
   mov es, ax
-  ; setup code + data stack
   mov ss, ax
-  mov sp, ax
-  mov bp, sp
+  mov sp, 0x800
+  mov di, sp
 
   call announce
-  call malloc_reset
-
-  call malloc_dump
 
   cli
 .halt:
@@ -91,13 +87,9 @@ start:
 %include "printf.inc"
 %include "print.asm"
 
-%include "popcnt.asm"
-
 %include "intr.asm"
 %include "debug.asm"
 
-%include "malloc.asm"
-
 times 512 nop
 
 align 512