drm/xe/guc: Fix CFI violation in debugfs access.

xe_guc_print_info is void-returning, but the function pointer it is
assigned to expects an int-returning function, leading to the following
CFI error:

[ 206.873690] CFI failure at guc_debugfs_show+0xa1/0xf0 [xe]
(target: xe_guc_print_info+0x0/0x370 [xe]; expected type: 0xbe3bc66a)

Fix this by updating xe_guc_print_info to return an integer.

Fixes: e15826bb3c2c ("drm/xe/guc: Refactor GuC debugfs initialization")
Signed-off-by: Daniele Ceraolo Spurio <[e-mail]>
Cc: Michal Wajdeczko <[e-mail]>
Cc: George D Sworo <[e-mail]>
Reviewed-by: Michal Wajdeczko <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
(cherry picked from commit dd8ea2f2ab71b98887fdc426b0651dbb1d1ea760)
Signed-off-by: Thomas Hellström <[e-mail]>

drivers/gpu/drm/xe/xe_guc.c

···
 	return xe_guc_submit_start(guc);
 }
 
-void xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p)
+int xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p)
 {
 	struct xe_gt *gt = guc_to_gt(guc);
 	unsigned int fw_ref;
···
 	if (!IS_SRIOV_VF(gt_to_xe(gt))) {
 		fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
 		if (!fw_ref)
-			return;
+			return -EIO;
 
 		status = xe_mmio_read32(&gt->mmio, GUC_STATUS);
 
···
 
 	drm_puts(p, "\n");
 	xe_guc_submit_print(guc, p);
+
+	return 0;
 }
 
 /**

drivers/gpu/drm/xe/xe_guc.h

···
 int xe_guc_self_cfg64(struct xe_guc *guc, u16 key, u64 val);
 void xe_guc_irq_handler(struct xe_guc *guc, const u16 iir);
 void xe_guc_sanitize(struct xe_guc *guc);
-void xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p);
+int xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p);
 int xe_guc_reset_prepare(struct xe_guc *guc);
 void xe_guc_reset_wait(struct xe_guc *guc);
 void xe_guc_stop_prepare(struct xe_guc *guc);