Provide coreboot coding style formalisation file for clang-format

The Clang project has a powerful code rewrite engine in the form
of LibFormat. A auxiliary tool is provided called `clang-format'
that can take a coding style formalisation file and rewrite your
code to conform to this style. Further, a wrapper script called
`git-clang-format' is also provided that can hook pre-commits
potentially replacing our slow and poor coverage regexp scripts
on pre-commits.

Herein we provide essentially the Linux Style Guide formalism.

Change-Id: Ica2207fdb8a4702793fa73eba6293b7b36ea9050
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/8036
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

.clang-format

@@ -0,0 +1,6 @@
+BasedOnStyle: LLVM
+IndentWidth: 8
+UseTab: Always
+BreakBeforeBraces: Linux
+AllowShortIfStatementsOnASingleLine: false
+IndentCaseLabels: false