Beginning with gen7, newer devices repetitively redefine values
for the device info structure members.  This patch simplifies the
structure definitions by grouping member value definitions into the
existing GEN7_FEATURES #define and into the new GEN7_LP_FEATURES
and HSW_FEATURES #defines.

Specifically, GEN_DEFAULT_PIPEOFFSETS and IVB_CURSOR_OFFSETS are
added to GEN7_FEATURES and subsequent IVB definitions are simplified.

VLV_FEATURES is defined to differentiate and simplify the
gen7 low power (LP) devices.

HSW_FEATURES is defined and used to simplify all HSW+ devices
except for LP.

v2: Use VLV_FEATURES for the gen7 low power devices. (Jani)

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Wayne Boyer <wayne.boyer@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449091694-7681-1-git-send-email-wayne.boyer@intel.com