This patch converts the initrd table override mechanism to the table
upgrade mechanism by restricting its usage to the tables released with
compatibility and more recent revision.

This use case has been encouraged by the ACPI specification:

 1. OEMID:
    An OEM-supplied string that identifies the OEM.

 2. OEM Table ID:
    An OEM-supplied string that the OEM uses to identify the particular data
    table. This field is particularly useful when defining a definition
    block to distinguish definition block functions. OEM assigns each
    dissimilar table a new OEM Table Id.

 3. OEM Revision:
    An OEM-supplied revision number. Larger numbers are assumed to be newer
    revisions.

For OEMs, good practices will ensure consistency when assigning OEMID and
OEM Table ID fields in any table. The intent of these fields is to allow
for a binary control system that support services can use. Because many
support function can be automated...