m68k: Avoid pointless recursion in debug console rendering

The recursive call to console_putc to effect a carriage return is
needlessly slow and complicated. Instead, just clear the column counter
directly. Setup %a0 earlier to avoid a repeated comparison.

Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Tested-by: Stan Johnson <userm57@yahoo.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/a6104f41918bed4fd17f92c45df94ac7a5d30e40.1743115195.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

Author: fthain

arch/m68k/kernel/head.S

@@ -3533,19 +3533,16 @@ func_start	console_putc,%a0/%a1/%d0-%d7
 	tstl	%pc@(L(console_font))
 	jeq	L(console_exit)
 
+	lea	%pc@(L(console_globals)),%a0
+
 	/* Output character in d7 on console.
 	 */
 	movel	ARG1,%d7
 	cmpib	#'\n',%d7
-	jbne	1f
+	jne	L(console_not_lf)
 
-	/* A little safe recursion is good for the soul */
-	console_putc	#'\r'
-1:
-	lea	%pc@(L(console_globals)),%a0
+	clrl	%a0@(Lconsole_struct_cur_column)	/* implicit \r */
 
-	cmpib	#10,%d7
-	jne	L(console_not_lf)
 	movel	%a0@(Lconsole_struct_cur_row),%d0
 	movel	%a0@(Lconsole_struct_num_rows),%d1
 	cmpl	%d1,%d0