kernel: Reformat code using clang-format (#347)

* The coding format is too messy, reformat to improve readability
  and get closer to Linux kernel coding style.

* While at it, update .clang-format file to linux-mainline state.

kernel/sucompat.c

@@ -67,11 +67,11 @@ static inline bool __is_su_allowed(const void *ptr_to_check)
 
 	return true;
 }
-#define is_su_allowed(ptr)	__is_su_allowed((const void *)ptr)
+#define is_su_allowed(ptr) __is_su_allowed((const void *)ptr)
 
 static int ksu_sucompat_user_common(const char __user **filename_user,
-				const char *syscall_name,
-				const bool escalate)
+				    const char *syscall_name,
+				    const bool escalate)
 {
 	char path[sizeof(su)]; // sizeof includes nullterm already!
 	memset(path, 0, sizeof(path));