env: mmc: Correct partition comparison in mmc_offset_try_partition

The function mmc_offset_try_partition searches the MMC partition for
locating environment data, by comparing the partition names with config
"u-boot,mmc-env-parition". However, it only compares the first word-size
bytes (size of 'const char *'), which may make the function to find
unintended partition.

Correct the function not to partially compare the partition name with
config "u-boot,mmc-env-partition".

Fixes: c9e87ba6

 ("env: Save environment at the end of an MMC partition")
Signed-off-by: Hoyeonjiki Kim <jigi.kim@gmail.com>
Reviewed-by: Wolfgang Denk <wd@denx.de>

env/mmc.c

@@ -42,7 +42,7 @@ static inline int mmc_offset_try_partition(const char *str, int copy, s64 *val)
 		if (ret < 0)
 			return ret;
 
-		if (!strncmp((const char *)info.name, str, sizeof(str)))
+		if (!strncmp((const char *)info.name, str, sizeof(info.name)))
 			break;
 	}