Add sys/types.h to dmi.h and do not rely on other files to include
all needed headers in Linux land. I ran into compile problems with
rtw88 otherwise.
MFC after: 3 days
dmi function are used to get smbios values.
The DRM subsystem and drivers use it to enabled (or not) quirks.
Reviewed by: hselasky
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D26046