BACKPORT: arm64: only consider memblocks with NOMAP cleared for linear mapping

BACKPORT: arm64: only consider memblocks with NOMAP cleared for linear mapping

Take the new memblock attribute MEMBLOCK_NOMAP into account when
deciding whether a certain region is or should be covered by the
kernel direct mapping.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Change-Id: Id7346a09bb3aee5e9a5ef8812251f80cf8265532
(cherry picked from commit 68709f45385aeddb0ca96a060c0c8259944f321b)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>