x86: coreboot: Drop sysinfo.c

sysinfo.c only contains the lib_sysinfo data structure which
is used/filled by tables.c. This split was introduced by importing
code from libpayload originally, but to keep the code simple, add
the single line of actual code to tables.c

Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>