arm64: Add AMPERE1 to the Spectre-BHB affected list

arm64: Add AMPERE1 to the Spectre-BHB affected list

Per AmpereOne erratum AC03_CPU_12, "Branch history may allow control of
speculative execution across software contexts," the AMPERE1 core needs the
bhb clearing loop to mitigate Spectre-BHB, with a loop iteration count of
11.

Signed-off-by: D Scott Phillips <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: James Morse <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>