Fix MD025 warnings

The following warnings are generated by using markdownlint analysis:
```
ipmi_flash.md:20 MD025/single-title/single-h1 Multiple top-level headings in the same document [Context: "# The state of fileOpen() per ..."]
ipmi_flash.md:36 MD025/single-title/single-h1 Multiple top-level headings in the same document [Context: "# The states in the Firmware H..."]
ipmi_flash.md:104 MD025/single-title/single-h1 Multiple top-level headings in the same document [Context: "# Expected State Transition Se..."]
```
Refer to markdown-lint [1] to fix MD025
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/025-single-h1.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I0179beddc1c2f45e9b8567a006e7d75b12021a25
diff --git a/ipmi_flash.md b/ipmi_flash.md
index 717404a..fd9ed99 100644
--- a/ipmi_flash.md
+++ b/ipmi_flash.md
@@ -17,7 +17,7 @@
 
 The two files are only present once their corresponding blob has been opened.
 
-# The state of fileOpen() per state
+## The state of fileOpen() per state
 
 You can only open one file at a time, and some of the states exist only when a
 file is open.
@@ -33,9 +33,9 @@
 | `updateStarted`         | `true`     |
 | `updatedCompleted`      | `true`     |
 
-# The states in the Firmware Handler State Machine
+## The states in the Firmware Handler State Machine
 
-## `notYetStarted`
+### `notYetStarted`
 
 **The starting state.**
 
@@ -45,7 +45,7 @@
 - `open(/flash/verify)`
 - `open(/flash/update)`
 
-## `uploadInProgress`
+### `uploadInProgress`
 
 **The BMC is expecting to receive bytes.**
 
@@ -55,7 +55,7 @@
 
 - `commit(/flash/*)` returns false
 
-## `verificationPending`
+### `verificationPending`
 
 **The BMC is ready for verification or more bytes.**
 
@@ -69,7 +69,7 @@
 
 - `commit(/flash/verify)` `state -> verificationStarted`
 
-## `verificationStarted`
+### `verificationStarted`
 
 **The verification process has started, no more writes allowed.**
 
@@ -77,7 +77,7 @@
 
 - `close(/flash/verify)` `state -> verificationCompleted`
 
-## `verificationCompleted`
+### `verificationCompleted`
 
 **The verification process has completed.**
 
@@ -87,21 +87,21 @@
 - `open(/flash/verify)`
 - `open(/flash/update)`
 
-## `updatePending`
+### `updatePending`
 
 **The update process is pending.**
 
-## `updateStarted`
+### `updateStarted`
 
 **The update process has started.**
 
 - `open(/flash/*)`r eturns false because `fileOpen() == true`
 
-## `updatedCompleted`
+### `updatedCompleted`
 
 **The update has completed (optional state to reach)**
 
-# Expected State Transition Sequence
+## Expected State Transition Sequence
 
 If verification fails, the state still transitions to `verificationCompleted`
 and similarly, if the update fails the state still transitions to