boot: Add EFISTUB and refactor boot protocols

boot/kernel.ld

@@ -7,6 +7,7 @@ PHDRS {
     dynamic PT_DYNAMIC  FLAGS(6);
     percpu  PT_LOAD     FLAGS(6);
     cmdline 0x60000005;
+    boot    0x60000008;
 }
 
 SECTIONS
@@ -62,6 +63,10 @@ SECTIONS
         *(.data .data.*)
     } :data
 
+    .boot : {
+        KEEP(*(.boot.info))
+    } :data :boot
+
     .dynsym : {
         __ld_dynsym_start = .;
         KEEP(*(.dynsym*))