fastboot: fix partition name truncation in environment lookup

strlcat() need to be passed the full buffer length. The incorrect call
caused truncation of partition names for fastboot_raw_partition_... and
fastboot_partition_alias_... env lookup to much less than PART_NAME_LEN.

Fixes: 69a752983171 ("fastboot: Fix possible buffer overrun")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/fastboot/fb_mmc.c b/drivers/fastboot/fb_mmc.c
index cbb3f7b..2738dc8 100644
--- a/drivers/fastboot/fb_mmc.c
+++ b/drivers/fastboot/fb_mmc.c
@@ -40,7 +40,7 @@
 
 	/* check for raw partition descriptor */
 	strcpy(env_desc_name, "fastboot_raw_partition_");
-	strlcat(env_desc_name, name, PART_NAME_LEN);
+	strlcat(env_desc_name, name, sizeof(env_desc_name));
 	raw_part_desc = strdup(env_get(env_desc_name));
 	if (raw_part_desc == NULL)
 		return -ENODEV;
@@ -114,7 +114,7 @@
 
 		/* check for alias */
 		strcpy(env_alias_name, "fastboot_partition_alias_");
-		strlcat(env_alias_name, name, PART_NAME_LEN);
+		strlcat(env_alias_name, name, sizeof(env_alias_name));
 		aliased_part_name = env_get(env_alias_name);
 		if (aliased_part_name != NULL)
 			ret = do_get_part_info(dev_desc, aliased_part_name,