tests: fs: Ensure file_path includes max file name length

A hardcoded path lenth of 80 will not be able to suppor the full length
of 255 when LFN is enabled. This does produce a compiler error,
thankfully, this is only applicable to the test cases.

Signed-off-by: Roman Vaughan <nzsmartie@gmail.com>
Signed-off-by: David Brown <david.brown@linaro.org>

tests/subsys/fs/fat_fs_api/src/test_fat_dir.c

diff --git a/tests/subsys/fs/fat_fs_api/src/test_fat_dir.c b/tests/subsys/fs/fat_fs_api/src/test_fat_dir.c
index e79b36e..22cfb05 100644
--- a/tests/subsys/fs/fat_fs_api/src/test_fat_dir.c
+++ b/tests/subsys/fs/fat_fs_api/src/test_fat_dir.c
@@ -106,7 +106,7 @@
 	int res;
 	struct fs_dir_t dirp;
 	static struct fs_dirent entry;
-	char file_path[80];
+	char file_path[80 + MAX_FILE_NAME];
 
 	TC_PRINT("\nrmdir tests:\n");