arm64: kdump: do not map crashkernel region specifically

arm64: kdump: do not map crashkernel region specifically

After taking off the protection functions on crashkernel memory region,
there's no need to map crashkernel region with page granularity during
linear mapping.

With this change, the system can make use of block or section mapping
on linear region to largely improve perforcemence during system bootup
and running.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20230407011507.17572-3-bhe@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>