drm: Perform cmdline mode parsing during connector initialisation

i915.ko has a custom fbdev initialisation routine that aims to preserve
the current mode set by the BIOS, unless overruled by the user. The
user's wishes are determined by what, if any, mode is specified on the
command line (via the video= parameter). However, that command line mode
is first parsed by drm_fb_helper_initial_config() which is called after
i915.ko's custom initial_config() as a fallback method. So in order for
us to honour it, we need to move the cmdline parser earlier. If we
perform the connector cmdline parsing as soon as we initialise the
connector, that cmdline mode and forced status is then available even if
the fbdev helper is not compiled in or never called.

We also then expose the cmdline user mode in the connector mode lists.

v2: Rebase after connector->name upheaval.

v3: Adapt mga200 to look for the cmdline mode in the new place. Nicely
simplifies things while at that.

v4: Fix checkpatch.

v5: Select FB_CMDLINE to adapt to the changed fbdev patch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=73154
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> (v2)
Cc: dri-devel@lists.freedesktop.org
Cc: Julia Lemire <jlemire@matrox.com>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 45f04de..83485ab 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -1483,11 +1483,7 @@
 {
 	struct drm_device *dev = connector->dev;
 	struct mga_device *mdev = (struct mga_device*)dev->dev_private;
-	struct mga_fbdev *mfbdev = mdev->mfbdev;
-	struct drm_fb_helper *fb_helper = &mfbdev->helper;
-	struct drm_fb_helper_connector *fb_helper_conn = NULL;
 	int bpp = 32;
-	int i = 0;
 
 	if (IS_G200_SE(mdev)) {
 		if (mdev->unique_rev_id == 0x01) {
@@ -1537,21 +1533,14 @@
 	}
 
 	/* Validate the mode input by the user */
-	for (i = 0; i < fb_helper->connector_count; i++) {
-		if (fb_helper->connector_info[i]->connector == connector) {
-			/* Found the helper for this connector */
-			fb_helper_conn = fb_helper->connector_info[i];
-			if (fb_helper_conn->cmdline_mode.specified) {
-				if (fb_helper_conn->cmdline_mode.bpp_specified) {
-					bpp = fb_helper_conn->cmdline_mode.bpp;
-				}
-			}
-		}
+	if (connector->cmdline_mode.specified) {
+		if (connector->cmdline_mode.bpp_specified)
+			bpp = connector->cmdline_mode.bpp;
 	}
 
 	if ((mode->hdisplay * mode->vdisplay * (bpp/8)) > mdev->mc.vram_size) {
-		if (fb_helper_conn)
-			fb_helper_conn->cmdline_mode.specified = false;
+		if (connector->cmdline_mode.specified)
+			connector->cmdline_mode.specified = false;
 		return MODE_BAD;
 	}