acpi: take oem_id in build_header(), optionally

acpi: take oem_id in build_header(), optionally

This patch is the continuation of commit 8870ca0e94f2 ("acpi: support
specified oem table id for build_header"). It will allow us to control the
OEM ID field too in the SDT header.

Cc: "Michael S. Tsirkin" <[email protected]> (supporter:ACPI/SMBIOS)
Cc: Igor Mammedov <[email protected]> (supporter:ACPI/SMBIOS)
Cc: Xiao Guangrong <[email protected]> (maintainer:NVDIMM)
Cc: Shannon Zhao <[email protected]> (maintainer:ARM ACPI Subsystem)
Cc: Paolo Bonzini <[email protected]> (maintainer:X86)
Cc: Richard W.M. Jones <[email protected]>
Cc: Aleksei Kovura <[email protected]>
Cc: Michael Tokarev <[email protected]>
Cc: Steven Newbury <[email protected]>
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1248758
LP: https://bugs.launchpad.net/qemu/+bug/1533848
Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Shannon Zhao <[email protected]>