Introduce clang-format

An automated and opinionated style for code. We can decide to change the
style and have the source updated by the clang-format tool by running:

    make format

I've based the style on the Google style with exceptions to better
match
the current source style.

Change-Id: I43f85c7d4ce02ca999805558b25fcab2e43859c6
diff --git a/src/dlog.c b/src/dlog.c
index c4d49ce..0af7eb5 100644
--- a/src/dlog.c
+++ b/src/dlog.c
@@ -1,13 +1,16 @@
 #include "dlog.h"
 
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stddef.h>
-#include <stdarg.h>
 
 #include "arch.h"
 #include "spinlock.h"
 #include "std.h"
 
+/* Keep macro alignment */
+/* clang-format off */
+
 #define FLAG_SPACE 0x01
 #define FLAG_ZERO  0x02
 #define FLAG_MINUS 0x04
@@ -16,6 +19,8 @@
 #define FLAG_UPPER 0x20
 #define FLAG_NEG   0x40
 
+/* clang-format on */
+
 /*
  * Prints a raw string to the debug log and returns its length.
  */
@@ -200,27 +205,23 @@
 
 			/* Handle the format specifier. */
 			switch (p[1]) {
-			case 's':
-				{
-					char *str = va_arg(args, char *);
-					print_string(str, str, w, flags, ' ');
-				}
+			case 's': {
+				char *str = va_arg(args, char *);
+				print_string(str, str, w, flags, ' ');
 				p++;
-				break;
+			} break;
 
 			case 'd':
-			case 'i':
-				{
-					int v = va_arg(args, int);
-					if (v < 0) {
-						flags |= FLAG_NEG;
-						v = -v;
-					}
-
-					print_num((size_t)v, 10, w, flags);
+			case 'i': {
+				int v = va_arg(args, int);
+				if (v < 0) {
+					flags |= FLAG_NEG;
+					v = -v;
 				}
+
+				print_num((size_t)v, 10, w, flags);
 				p++;
-				break;
+			} break;
 
 			case 'X':
 				flags |= FLAG_UPPER;