acpi/ghes: better name the offset of the hardware error firmware

acpi/ghes: better name the offset of the hardware error firmware

The hardware error firmware is where HEST error structures are
stored. Those can be GHESv2, but they can also be other types.

Better name the location of the hardware error.

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: <ddbb94294bafee998f12fede3ba0b05dae5ee45f.1736945236.git.mchehab+huawei@kernel.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>