mmc: core: Remove unnecessary error checks and change return type

The error checks in mmc_blk_add_debugfs() and mmc_blk_remove_debugfs()
are extraneous. Therefore, this patch removes all error checks from
both functions.
Additionally, mmc_blk_add_debugfs() has been changed to return void
instead of an integer value that was never used. This simplifies the
function and improves its clarity.
Signed-off-by: Yeqi Fu <asuk4.q@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20230518101216.369970-1-asuk4.q@gmail.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/block.c

@@ -2899,12 +2899,12 @@ static const struct file_operations mmc_dbg_ext_csd_fops = {
 	.llseek		= default_llseek,
 };
 
-static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
+static void mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
 {
 	struct dentry *root;
 
 	if (!card->debugfs_root)
-		return 0;
+		return;
 
 	root = card->debugfs_root;
 
@@ -2913,19 +2913,13 @@ static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
 			debugfs_create_file_unsafe("status", 0400, root,
 						   card,
 						   &mmc_dbg_card_status_fops);
-		if (!md->status_dentry)
-			return -EIO;
 	}
 
 	if (mmc_card_mmc(card)) {
 		md->ext_csd_dentry =
 			debugfs_create_file("ext_csd", S_IRUSR, root, card,
 					    &mmc_dbg_ext_csd_fops);
-		if (!md->ext_csd_dentry)
-			return -EIO;
 	}
-
-	return 0;
 }
 
 static void mmc_blk_remove_debugfs(struct mmc_card *card,
@@ -2934,22 +2928,17 @@ static void mmc_blk_remove_debugfs(struct mmc_card *card,
 	if (!card->debugfs_root)
 		return;
 
-	if (!IS_ERR_OR_NULL(md->status_dentry)) {
-		debugfs_remove(md->status_dentry);
-		md->status_dentry = NULL;
-	}
+	debugfs_remove(md->status_dentry);
+	md->status_dentry = NULL;
 
-	if (!IS_ERR_OR_NULL(md->ext_csd_dentry)) {
-		debugfs_remove(md->ext_csd_dentry);
-		md->ext_csd_dentry = NULL;
-	}
+	debugfs_remove(md->ext_csd_dentry);
+	md->ext_csd_dentry = NULL;
 }
 
 #else
 
-static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
+static void mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
 {
-	return 0;
 }
 
 static void mmc_blk_remove_debugfs(struct mmc_card *card,