arm64/kexec: Fix missing extra range for crashkres_low.

arm64/kexec: Fix missing extra range for crashkres_low.

Like crashk_res, Calling crash_exclude_mem_range function with
crashk_low_res area would need extra crash_mem range too.

Add one more extra cmem slot in case of crashk_low_res is used.

Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Fixes: 944a45abfabc ("arm64: kdump: Reimplement crashkernel=X")
Cc: <stable@vger.kernel.org> # 5.19.x
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220831103913.12661-1-ppbuk5246@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>