drm/i915: merge gen checks to use range

Instead of using IS_GEN() for consecutive gen checks, let's pass the
range to IS_GEN_RANGE(). By code inspection these were the ranges deemed
necessary for spatch:

@@
expression e;
@@
(
- IS_GEN(e, 3) || IS_GEN(e, 2)
+ IS_GEN_RANGE(e, 2, 3)
|
- IS_GEN(e, 3) || IS_GEN(e, 4)
+ IS_GEN_RANGE(e, 3, 4)
|
- IS_GEN(e, 5) || IS_GEN(e, 6)
+ IS_GEN_RANGE(e, 5, 6)
|
- IS_GEN(e, 6) || IS_GEN(e, 7)
+ IS_GEN_RANGE(e, 6, 7)
|
- IS_GEN(e, 7) || IS_GEN(e, 8)
+ IS_GEN_RANGE(e, 7, 8)
|
- IS_GEN(e, 8) || IS_GEN(e, 9)
+ IS_GEN_RANGE(e, 8, 9)
|
- IS_GEN(e, 10) || IS_GEN(e, 9)
+ IS_GEN_RANGE(e, 9, 10)
|
- IS_GEN(e, 9) || IS_GEN(e, 10)
+ IS_GEN_RANGE(e, 9, 10)
)

After conversion, checking we don't have any missing IS_GEN_RANGE() ||
IS_GEN() was also done.

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/20181212181044.15886-3-lucas.demarchi@intel.com