x86: OLPC: Cleanup config maze completely

Neither CONFIG_OLPC_OPENFIRMWARE nor CONFIG_OLPC_OPENFIRMWARE_DT are
really necessary.

OLPC selects OLPC_OPENFIRMWARE unconditionally, so move the "select
OF" part under OLPC config option and fixup the dependencies in
Makefiles and code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andres Salomon <dilinger@queued.net>

arch/x86/kernel/head_32.S

@@ -137,7 +137,7 @@ ENTRY(startup_32)
 	movsl
 1:
 
-#ifdef CONFIG_OLPC_OPENFIRMWARE
+#ifdef CONFIG_OLPC
 	/* save OFW's pgdir table for later use when calling into OFW */
 	movl %cr3, %eax
 	movl %eax, pa(olpc_ofw_pgd)