EDAC/amd64: Get UMC channel from the 6th nibble for Hygon

hygon inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7DX6V


CVE: NA

---------------------------

On Hygon family 18h platforms, we look at the 6th nibble(bit 20~23)
in the instance_id to derive the channel number.

Signed-off-by: Pu Wen <puwen@hygon.cn>