powerpc/64e: drop unused TLB miss handlers

There are two possibilities for book3e_htw_mode, PPC_HTW_E6500 or
PPC_HTW_NONE.

The TLB miss handlers are patched to use, respectively:
  - exc_[data|indstruction]_tlb_miss_e6500_book3e
  - exc_[data|indstruction]_tlb_miss_bolted_book3e

Which means the default handlers are never used.  Remove those, and use
the bolted handlers (PPC_HTW_NONE) by default.

Link: https://lkml.kernel.org/r/9a670adc1771fb1871fba93ace5372f7eadc286f.1719928057.git.christophe.leroy@csgroup.eu


Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>