acpi/ghes: simplify the per-arch caller to build HEST table

acpi/ghes: simplify the per-arch caller to build HEST table

The GHES driver requires not only a HEST table, but also a
separate firmware file to store Error Structure records.
It can't do one without the other.

Simplify the caller logic for it to require one function.

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <9584bb8953385e165681d5d185c503f8df8ef42f.1736945236.git.mchehab+huawei@kernel.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>