powerpc: Remove Kconfig support for PPC_MERGE

There are no users of PPC_MERGE in tree so we can get rid of it.
It was a hold over from the arch/ppc days.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/Kconfig

@@ -19,9 +19,6 @@ config WORD_SIZE
 	default 64 if PPC64
 	default 32 if !PPC64
 
-config PPC_MERGE
-	def_bool y
-
 config MMU
 	bool
 	default y