drm/crtc: fix uninitialized variable use

Commit 3823119b ("drm/crtc: Fix uninit-value bug in
drm_mode_setcrtc") was supposed to fix use of an uninitialized variable,
but introduced another.

num_connectors is only initialized if crtc_req->count_connectors > 0,
but it's used regardless. Fix it.

Fixes: 3823119b ("drm/crtc: Fix uninit-value bug in drm_mode_setcrtc")
Cc: syzbot+4fad2e57beb6397ab2fc@syzkaller.appspotmail.com
Cc: Ziqi Zhao <astrajoan@yahoo.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231208131238.2924571-1-jani.nikula@intel.com

drivers/gpu/drm/drm_crtc.c

@@ -715,7 +715,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
 	struct drm_mode_set set;
 	uint32_t __user *set_connectors_ptr;
 	struct drm_modeset_acquire_ctx ctx;
-	int ret, i, num_connectors;
+	int ret, i, num_connectors = 0;
 
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return -EOPNOTSUPP;
@@ -850,7 +850,6 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
 			goto out;
 		}
 
-		num_connectors = 0;
 		for (i = 0; i < crtc_req->count_connectors; i++) {
 			connector_set[i] = NULL;
 			set_connectors_ptr = (uint32_t __user *)(unsigned long)crtc_req->set_connectors_ptr;