x86: unify arch/x86/kernel/Makefile(s)

Combine the 32 and 64 bit specific Makefiles in one file.
While doing so link order was (almost) preserved on 32 bit
but on 64 bit link order changed a lot.

Patch was checked with defconfig + allyesconfig builds.
The same .o files were linked in these configurations.

To keep readability of the Makefiles a few Kconfig
symbols was added/modified and it was checked that
they were not used anywhere else.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/Kconfig.debug

@@ -75,8 +75,7 @@ config X86_FIND_SMP_CONFIG
 
 config X86_MPPARSE
 	def_bool y
-	depends on X86_LOCAL_APIC && !X86_VISWS
-	depends on X86_32
+	depends on (X86_32 && (X86_LOCAL_APIC && !X86_VISWS)) || X86_64
 
 config DOUBLEFAULT
 	default y