fs/erofs: silence erofs_probe()

fs_set_blk_dev() probes all file-systems until it finds one that matches
the volume. We do not expect any console output for non-matching
file-systems.

Convert error messages in erofs_read_superblock() to debug output.

Fixes: 830613f8f5bb ("fs/erofs: add erofs filesystem support")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Huang Jianan <jnhuang95@gmail.com>
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 4cca322..8277d9b 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -65,14 +65,14 @@
 
 	ret = erofs_blk_read(data, 0, 1);
 	if (ret < 0) {
-		erofs_err("cannot read erofs superblock: %d", ret);
+		erofs_dbg("cannot read erofs superblock: %d", ret);
 		return -EIO;
 	}
 	dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
 
 	ret = -EINVAL;
 	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
-		erofs_err("cannot find valid erofs superblock");
+		erofs_dbg("cannot find valid erofs superblock");
 		return ret;
 	}