hv: fixup relocation delta for symbols belong to entry section

This is to enable relocation for code32.

- RIP relative addressing is available in x86-64 only so we manually add
  relocation delta to the target symbols to fixup code32.

- both code32 and code64 need to load GDT hence both need to fixup GDT
  pointer. This patch declares separate GDT pointer cpu_primary64_gdt_ptr
  for code64 to avoid double fixup.

- manually fixup cpu_primary64_gdt_ptr in code64, but not rely on relocate()
  to do that. Otherwise it's very confusing that symbols from same file could
  be fixed up externally by relocate() or self-relocated.

- to make it clear, define a new symbol ld_entry_end representing the end of
  the boot code that needs manually fixup, and use this symbol in relocate()
  to filter out all symbols belong to the entry sections.

Tracked-On: #4441
Reviewed-by: Fengwei Yin <fengwei.yin@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>

hypervisor/bsp/ld/link_ram.ld.in

@@ -20,6 +20,7 @@ SECTIONS
     .entry :
     {
         KEEP(*(entry)) ;
+	ld_entry_end = . ;
 
     } > ram