x86/amd_nb: Get DF ID from F5 device for Hygon family 18h model 6h

hygon inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I92H9L


CVE: NA

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The DF ID should be get from DF F5 device for Hygon family 18h
model 6h processor.

Fixes: 950b6f3c ("x86/amd_nb: Add support for Hygon family 18h model 6h")
Signed-off-by: Pu Wen <puwen@hygon.cn>