drm/i915/bdw: Support eDP PSR

Broadwell PSR support is a superset of Haswell. With this simple
register base calculation, everything that worked on HSW for eDP PSR
should work on BDW.

Note that Broadwell provides additional PSR support. This is not
addressed at this time.

v2: Make the HAS_PSR include BDW

v3: Use the correct offset (I had incorrectly used one from my faulty
brain) (Art!)

v4: It helps if you git add

v5: Be explicit about not setting min link entry time for BDW. This
should be no functional change over v4 (Jani)

Reviewed-by: Art Runyan <arthur.j.runyan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5deeb19..9944b26 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1810,7 +1810,7 @@
 #define HAS_DDI(dev)		(INTEL_INFO(dev)->has_ddi)
 #define HAS_POWER_WELL(dev)	(IS_HASWELL(dev) || IS_BROADWELL(dev))
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)
-#define HAS_PSR(dev)		(IS_HASWELL(dev))
+#define HAS_PSR(dev)		(IS_HASWELL(dev) || IS_BROADWELL(dev))
 
 #define INTEL_PCH_DEVICE_ID_MASK		0xff00
 #define INTEL_PCH_IBX_DEVICE_ID_TYPE		0x3b00