powerpc/64e: fix CONFIG_RELOCATABLE build warnings

CONFIG_RELOCATABLE=y causes build warnings from unresolved relocations.
Fix these by using TOC addressing for these cases.

Commit 24d33ac5

 ("powerpc/64s: Make prom_init require RELOCATABLE")
caused some 64e configs to select RELOCATABLE resulting in these
warnings, but the underlying issue was already there.

This passes basic qemu testing.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210630074621.2109197-3-npiggin@gmail.com