powerpc/mm/book3e/64: Remove unsupported 64Kpage size from 64bit booke

We have in Kconfig

config PPC_64K_PAGES
	bool "64k page size"
	depends on !PPC_FSL_BOOK3E && (44x || PPC_BOOK3S_64 || PPC_BOOK3E_64)
	select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64

Only supported BOOK3E 64 bit platforms is FSL_BOOK3E. Remove the dead 64k page
support code from 64bit nohash.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>