printk: Make printk_emit() local function.

printk_emit() is called from only devkmsg_write() in the same file.
Save object size by making it a local function.

Link: http://lkml.kernel.org/r/5cc99d2c-c408-34f7-d1fc-e1cd2a9e31da@i-love.sakura.ne.jp
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

include/linux/printk.h

@@ -166,11 +166,6 @@ int vprintk_emit(int facility, int level,
 asmlinkage __printf(1, 0)
 int vprintk(const char *fmt, va_list args);
 
-asmlinkage __printf(5, 6) __cold
-int printk_emit(int facility, int level,
-		const char *dict, size_t dictlen,
-		const char *fmt, ...);
-
 asmlinkage __printf(1, 2) __cold
 int printk(const char *fmt, ...);