powerpc/64s: Move and rename do_bad_slb_fault as it is not hash specific

slb.c is hash-specific SLB management, but do_bad_slb_fault deals with
segment interrupts that occur with radix MMU as well.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211201144153.2456614-5-npiggin@gmail.com