Fix MD056 warnings

The following warnings are generated by using markdownlint analysis:
```
docs/oem-extension-numbering.md:118:33 MD056/table-column-count Table column count [Expected: 4; Actual: 3; Too few cells, row will be missing data]
docs/oem-extension-numbering.md:121:33 MD056/table-column-count Table column count [Expected: 4; Actual: 3; Too few cells, row will be missing data]
```

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: If6f30b974831325b14b783b3339ddcf5c186bc83
diff --git a/docs/oem-extension-numbering.md b/docs/oem-extension-numbering.md
index 6309645..29daa3c 100644
--- a/docs/oem-extension-numbering.md
+++ b/docs/oem-extension-numbering.md
@@ -115,10 +115,10 @@
 
 | Bytes | Bits | Identifier     | Description                                   |
 | :---: | :--: | :------------- | :-------------------------------------------- |
-|   0   |      | devAndDir      |
+|   0   |      | devAndDir      |                                               |
 |       | 7:1  | dev            | 7-bit I2C device address.                     |
 |       |  0   | isRead         | 1 = read, 0 = write.                          |
-|   1   |      | stepFlags      |
+|   1   |      | stepFlags      |                                               |
 |       |  7   | i2cFlagRecvLen | 1 if block read, else regular; see table.     |
 |       |  6   | i2cFlagNoStart | 1 to suppress I2C start.                      |
 |       | 5:0  |                | Reserved(0)                                   |