test:dm:fix typo

Fix typos in the 'test/dm' directory.

Signed-off-by: Yuepeng Xing <xingyuepeng@eswincomputing.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/scmi.c b/test/dm/scmi.c
index 795f207..93c7d08 100644
--- a/test/dm/scmi.c
+++ b/test/dm/scmi.c
@@ -6,7 +6,7 @@
  * uclass devices probe when a SCMI server exposes resources.
  *
  * Note in test.dts the protocol@10 node in scmi node. Protocol 0x10 is not
- * implemented in U-Boot SCMI components but the implementation is exepected
+ * implemented in U-Boot SCMI components but the implementation is expected
  * to not complain on unknown protocol IDs, as long as it is not used. Note
  * in test.dts tests that SCMI drivers probing does not fail for such an
  * unknown SCMI protocol ID.