[TF-A] About erratum in TF-A

Hi Boyan,

Some questions about erratum in TF-A: 1 Why workaround's flag is 0? In my mind, all flag should be 1 because there is func to check cpu revisions, such as check_errata_2326639.

43438ad1a patch: +ERRATA_N2_2326639 ?=0

2 After e444763d6(shorten errata flag defines) patch, introduce CPU_FLAG_LIST, Is the workaround's flag change to 1?

e444763d6 patch: -ERRATA_N2_2326639 ?=0 +CPU_FLAG_LIST += ERRATA_N2_2326639

Regards, Ming