soc: fsl: handle RCPM errata A-008646 on SoC LS1021A

Hardware issue:
- Reading register RCPM_IPPDEXPCR1 always return zero, this causes
  system firmware could not get correct information and wrongly do
  clock gating for all wakeup source IP during system suspend. Then
  those IPs will never get chance to wake system.

Workaround:
- Copy register RCPM_IPPDEXPCR1's setting to register SCFG_SPARECR8
  to allow system firmware's psci method read it and do things accordingly.

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>