top: add .clang-format

Add a clang-format to automate consistent code formatting.

Automating coding style reformatting removes a lot of manual
checkpatch-type fixups, and can easily be implemented as a linter in
code review environments.

Signed-off-by: Olof Johansson <olof@lixom.net>

.clang-format

@@ -0,0 +1,16 @@
+AlignConsecutiveAssignments: true
+AlignEscapedNewlines: Left
+AlignTrailingComments: true
+AllowShortFunctionsOnASingleLine: None
+BraceWrapping:
+  AfterFunction: true
+BreakBeforeBraces: Custom
+BreakStringLiterals: false
+ContinuationIndentWidth: 8
+Cpp11BracedListStyle: false
+IndentWidth: 8
+ReflowComments: false
+SortIncludes: false
+SpacesInContainerLiterals: false
+TabWidth: 8
+UseTab: Always