drm/i915: Extend private i915_param_named macro with description

We're always specifying description of each module param in
separate macro. Let's combine description into our main macro.
Started with Coccinelle, followed by minor cleanup.

@match1@
declarer name MODULE_PARM_DESC;
identifier n;
constant c;
@@
(
-	MODULE_PARM_DESC(n, c);
)

@fix1 depends on match1@
declarer name i915_param_named;
declarer name i915_param_named_unsafe;
identifier match1.n;
constant match1.c;
@@
(
	i915_param_named(n, ...
+	, c
	);
|
	i915_param_named_unsafe(n, ...
+	, c
	);
)
Suggested-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170914150805.28376-4-michal.wajdeczko@intel.com