dm: sysinfo: Shorten the SYSINFO_ID prefix

dm: sysinfo: Shorten the SYSINFO_ID prefix

We are about to add a large number of new entries. Update the prefix to
be a little shorter.

For SMBIOS items, use SYSID_SM_ (for System Management) which is enough
to distinguish it. For now at least, it seems that most items will be
for SMBIOS.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Raymond Mao <raymond.mao@linaro.org>