mtd: nand: mxs: Replace magic number for bits per ECC level with macro

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/tools/mxsboot.c b/tools/mxsboot.c
index 6d48cfb..08219b3 100644
--- a/tools/mxsboot.c
+++ b/tools/mxsboot.c
@@ -48,6 +48,7 @@
 #define	MXS_NAND_DMA_DESCRIPTOR_COUNT		4
 #define	MXS_NAND_CHUNK_DATA_CHUNK_SIZE		512
 #define	MXS_NAND_METADATA_SIZE			10
+#define	MXS_NAND_BITS_PER_ECC_LEVEL		13
 #define	MXS_NAND_COMMAND_BUFFER_SIZE		32
 
 struct mx28_nand_fcb {
@@ -127,7 +128,7 @@
 
 static inline uint32_t mx28_nand_ecc_size_in_bits(uint32_t ecc_strength)
 {
-	return ecc_strength * 13;
+	return ecc_strength * MXS_NAND_BITS_PER_ECC_LEVEL;
 }
 
 static inline uint32_t mx28_nand_get_ecc_strength(uint32_t page_data_size,