drm/i915: simplify prefixes on device_info

Drop the intel prefix since all these structs are static and prefer
using the 3-letter prefix for each platform.

v2: also remove gen from the device info (Ville)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191224084012.24241-1-lucas.demarchi@intel.com