bug.h: introduce WARN_ONCE

Add WARN_ONCE definition to allow single time notification
of warnings to the user.
Taken from Linux kernel (4.17) with slight changes
(Removed __section(.data.once))

Signed-off-by: Ramon Fried <ramon.fried@gmail.com>
[trini: Drop the musb and dwc3 compat versions]
Signed-off-by: Tom Rini <trini@konsulko.com>

drivers/usb/dwc3/linux-compat.h

@@ -11,7 +11,6 @@
 #ifndef __DWC3_LINUX_COMPAT__
 #define __DWC3_LINUX_COMPAT__
 
-#define WARN(val, format, arg...)	debug(format, ##arg)
 #define dev_WARN(dev, format, arg...)	debug(format, ##arg)
 
 static inline size_t strlcat(char *dest, const char *src, size_t n)

drivers/usb/musb-new/linux-compat.h

@@ -5,12 +5,6 @@
 #include <linux/list.h>
 #include <linux/compat.h>
 
-#define WARN(condition, fmt, args...) ({	\
-	int ret_warn = !!condition;		\
-	if (ret_warn)				\
-		printf(fmt, ##args);		\
-	ret_warn; })
-
 #define device_init_wakeup(dev, a) do {} while (0)
 
 #define platform_data device_data

include/linux/bug.h

@@ -20,6 +20,13 @@
 	unlikely(__ret_warn_on);					\
 })
 
+#define WARN(condition, format...) ({                   \
+	int __ret_warn_on = !!(condition);              \
+	if (unlikely(__ret_warn_on))                    \
+		printf(format);                  \
+	unlikely(__ret_warn_on);                    \
+})
+
 #define WARN_ON_ONCE(condition)	({				\
 	static bool __warned;					\
 	int __ret_warn_once = !!(condition);			\
@@ -31,4 +38,15 @@
 	unlikely(__ret_warn_once);				\
 })
 
+#define WARN_ONCE(condition, format...) ({          \
+	static bool __warned;     \
+	int __ret_warn_once = !!(condition);            \
+								\
+	if (unlikely(__ret_warn_once && !__warned)) {       \
+		__warned = true;                \
+		WARN(1, format);                \
+	}                           \
+	unlikely(__ret_warn_once);              \
+})
+
 #endif	/* _LINUX_BUG_H */