MIPS: Loongson: Remove existing early_printk implementation

Removes the existing implementation of early_printk for fulong.  The old
implementation was based on the outdated board-specific dbg_io.c.

Since commit 8d60a903 dbg_io.c is not longer
needed; it will be removed by the next patch, and a new implementation of
early_printk will be added later.
Signed-off-by: NWu Zhangjin <wuzj@lemote.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/lemote/lm2e/prom.c

@@ -21,7 +21,6 @@
 extern unsigned long bus_clock;
 extern unsigned long cpu_clock_freq;
 extern unsigned int memsize, highmemsize;
-extern int putDebugChar(unsigned char byte);
 
 static int argc;
 /* pmon passes arguments in 32bit pointers */
@@ -90,8 +89,3 @@ do {									\
 void __init prom_free_prom_memory(void)
 {
 }
-
-void prom_putchar(char c)
-{
-	putDebugChar(c);
-}