[PATCH] powerpc/process: Fix uninitialised variable error

[Nick Desaulniers]

https://lore.kernel.org/linuxppc-dev/20200917024509.3253837-1-mpe@ellerman.id.au/

Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>
Tested-by: Nick Desaulniers <ndesaulniers at google.com>