acpi: build_xsdt: use acpi_table_begin()/acpi_table_end() instead of build_header()

acpi: build_xsdt: use acpi_table_begin()/acpi_table_end() instead of build_header()

it replaces error-prone pointer arithmetic for build_header() API,
with 2 calls to start and finish table creation,
which hides offsets magic from API user.

While at it switch to build_append_int_noprefix() to build
entries to other tables (which also removes some manual offset
calculations).

Signed-off-by: Igor Mammedov <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Message-Id: <20210924122802.1455362[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>