x86: all firmware tables must be paragraph aligned

On qemu-x86_64_defconfig the following was observed:

    => efidebug tables
    00000000000f0074  eb9d2d31-2d88-11d3-9a16-0090273fc14d  SMBIOS table

The SMBIOS configuration table does not point to a paragraph-aligned
(16 byte aligned) address. The reason is that in write_tables() rom_addr is
not aligned and copied to gd->arch.smbios_start.

The Simple Firmware Interface requires that the SFI table is paragraph-
aligned but our code does not guarantee this.

As all tables written in write_tables() must be paragraph-aligned, we
should implement the address rounding in write_tables() and not in table
specific routines like copy_pirq_routing_table().

Add paragraph-alignment in write_tables().

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>