powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8OHAZ
CVE: NA

Reference: https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20200330022023.3691-7-yanaijie@huawei.com/



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Now we support both 32 and 64 bit KASLR for fsl booke. Add document for
64 bit part and rename kaslr-booke32.rst to kaslr-booke.rst.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Cui GaoSheng <cuigaosheng1@huawei.com>
Signed-off-by: GUO Zihua <guozihua@huawei.com>