binman: Don't add compression attribute for uncompressed files

cbfsutil changed to skip adding a compression attribute if there is no
compression. Adjust the binman implementation to do the same.

This mirrors commit 105cdf5625 in coreboot.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
diff --git a/tools/binman/cbfs_util_test.py b/tools/binman/cbfs_util_test.py
index ee951d1..c3babbc 100755
--- a/tools/binman/cbfs_util_test.py
+++ b/tools/binman/cbfs_util_test.py
@@ -96,7 +96,7 @@
         self.assertEqual(arch, cbfs.arch)
         return cbfs
 
-    def _check_uboot(self, cbfs, ftype=cbfs_util.TYPE_RAW, offset=0x38,
+    def _check_uboot(self, cbfs, ftype=cbfs_util.TYPE_RAW, offset=0x28,
                      data=U_BOOT_DATA, cbfs_offset=None):
         """Check that the U-Boot file is as expected
 
@@ -122,7 +122,7 @@
         self.assertEqual(len(data), cfile.memlen)
         return cfile
 
-    def _check_dtb(self, cbfs, offset=0x38, data=U_BOOT_DTB_DATA,
+    def _check_dtb(self, cbfs, offset=0x28, data=U_BOOT_DTB_DATA,
                    cbfs_offset=None):
         """Check that the U-Boot dtb file is as expected
 
@@ -598,8 +598,8 @@
         data = cbw.get_data()
 
         cbfs = cbfs_util.CbfsReader(data)
-        self.assertEqual(0x38, cbfs.files['u-boot'].cbfs_offset)
-        self.assertEqual(0x78, cbfs.files['u-boot-dtb'].cbfs_offset)
+        self.assertEqual(0x28, cbfs.files['u-boot'].cbfs_offset)
+        self.assertEqual(0x68, cbfs.files['u-boot-dtb'].cbfs_offset)
 
 
 if __name__ == '__main__':