mtd: rawnand: Add a kernel doc to the ECC algorithm enumeration

Before moving it to the generic raw NAND core, ensure the enumeration
is properly described.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-mtd/20200827085208.16276-2-miquel.raynal@bootlin.com

include/linux/mtd/rawnand.h

@@ -92,6 +92,13 @@ enum nand_ecc_mode {
 	NAND_ECC_ON_DIE,
 };
 
+/**
+ * enum nand_ecc_algo - NAND ECC algorithm
+ * @NAND_ECC_UNKNOWN: Unknown algorithm
+ * @NAND_ECC_HAMMING: Hamming algorithm
+ * @NAND_ECC_BCH: Bose-Chaudhuri-Hocquenghem algorithm
+ * @NAND_ECC_RS: Reed-Solomon algorithm
+ */
 enum nand_ecc_algo {
 	NAND_ECC_UNKNOWN,
 	NAND_ECC_HAMMING,