log: optimize log/panic with attribute cold

Both logging and calls to panic are never in the critical path.
Use the GCC attribute cold to mark these functions as cold,
which generates more optimised code.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Reviewed-by: Vincent Jardin <vincent.jardin@6wind.com>

lib/librte_eal/common/include/rte_debug.h

@@ -86,6 +86,7 @@ void rte_dump_registers(void);
  * documentation.
  */
 void __rte_panic(const char *funcname , const char *format, ...)
+	__attribute__((cold))
 	__attribute__((noreturn))
 	__attribute__((format(printf, 2, 3)));
 

lib/librte_eal/common/include/rte_log.h

@@ -217,6 +217,7 @@ int rte_log_add_in_history(const char *buf, size_t size);
  *   - Negative on error.
  */
 int rte_log(uint32_t level, uint32_t logtype, const char *format, ...)
+	__attribute__((cold))
 	__attribute__((format(printf, 3, 4)));
 
 /**