drm/i915: Split Pineview device info into desktop and mobile

This allows the IS_PINEVIEW_<G|M> macros to be removed and avoid
duplication of device ids already defined in i915_pciids.h.

!IS_MOBILE check can be used in place of existing IS_PINEVIEW_G call
sites.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190326074057.27833-2-tvrtko.ursulin@linux.intel.com