drm/i915: replace IS_GEN<N> with IS_GEN(..., N)

Define IS_GEN() similarly to our IS_GEN_RANGE(). but use gen instead of
gen_mask to do the comparison. Now callers can pass then gen as a parameter,
so we don't require one macro for each gen.

The following spatch was used to convert the users of these macros:

@@
expression e;
@@
(
- IS_GEN2(e)
+ IS_GEN(e, 2)
|
- IS_GEN3(e)
+ IS_GEN(e, 3)
|
- IS_GEN4(e)
+ IS_GEN(e, 4)
|
- IS_GEN5(e)
+ IS_GEN(e, 5)
|
- IS_GEN6(e)
+ IS_GEN(e, 6)
|
- IS_GEN7(e)
+ IS_GEN(e, 7)
|
- IS_GEN8(e)
+ IS_GEN(e, 8)
|
- IS_GEN9(e)
+ IS_GEN(e, 9)
|
- IS_GEN10(e)
+ IS_GEN(e, 10)
|
- IS_GEN11(e)
+ IS_GEN(e, 11)
)

v2: use IS_GEN rather than GT_GEN and compare to info.gen rather than
    using the bitmask

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181212181044.15886-2-lucas.demarchi@intel.com

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -94,11 +94,11 @@ hangcheck_action_to_str(const enum intel_engine_hangcheck_action a)
 #define I915_MAX_SUBSLICES 8
 
 #define instdone_slice_mask(dev_priv__) \
-	(IS_GEN7(dev_priv__) ? \
+	(IS_GEN(dev_priv__, 7) ? \
 	 1 : INTEL_INFO(dev_priv__)->sseu.slice_mask)
 
 #define instdone_subslice_mask(dev_priv__) \
-	(IS_GEN7(dev_priv__) ? \
+	(IS_GEN(dev_priv__, 7) ? \
 	 1 : INTEL_INFO(dev_priv__)->sseu.subslice_mask[0])
 
 #define for_each_instdone_slice_subslice(dev_priv__, slice__, subslice__) \