xilinx-zynq: Revert "zynq: SMP crashkernel support"

This reverts commit 5d1a5900

.

Since the commit ("ARM: zynq: use physical cpuid in zynq_slcr_cpu_stop/start")
has fixed the hang issue in kdump, this patch can be reverted.

Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>