mtd: nand: Clarify Kconfig entry for software Hamming ECC entries

The software Hamming ECC correction implementation is referred as
MTD_NAND_ECC which is too generic. Rename it
MTD_NAND_ECC_SW_HAMMING. Also rename MTD_NAND_ECC_SMC which is an
SMC quirk in the Hamming implementation as
MTD_NAND_ECC_SW_HAMMING_SMC.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 79a8ff54..aa5a27f 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -230,12 +230,11 @@
 	  This enables read only access to SmartMedia formatted NAND
 	  flash. You can mount it with FAT file system.
 
-
 config SM_FTL
 	tristate "SmartMedia/xD new translation layer"
 	depends on BLOCK
 	select MTD_BLKDEVS
-	select MTD_NAND_ECC
+	select MTD_NAND_ECC_SW_HAMMING
 	help
 	  This enables EXPERIMENTAL R/W support for SmartMedia/xD
 	  FTL (Flash translation layer).