meta-ampere: mtjade: fix services start fail

Fix ampere-mac-update and ampere-gpio-handling starts failure,
including:
- Update ampere_update_mac.sh to recheck if the first MAC Address
reading fail. Also fix incorrect checking if setting new MAC Address
success or not.
- Fix typo in SCP failover service.

Tested:
1. Check if the ampere_update_mac.service starts succesfully.
2. Check if no error report from iS0_scp_auth_failure

Signed-off-by: Thang Q. Nguyen <thang@os.amperecomputing.com>
Change-Id: I6c03e352d8d51030d04cd303e438835e5b724afe