[PATCH] powerpc: udbg updates

The udbg low level io layer has an issue with udbg_getc() returning a
char (unsigned on ppc) instead of an int, thus the -1 if you had no
available input device could end up turned into 0xff, filling your
display with bogus characters. This fixes it, along with adding a little
blob to xmon to do a delay before exiting when getting an EOF and fixing
the detection of ADB keyboards in udbg_adb.c

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/xmon/xmon.c

@@ -450,7 +450,6 @@ int xmon_core(struct pt_regs *regs, int fromipi)
  leave:
 	cpu_clear(cpu, cpus_in_xmon);
 	xmon_fault_jmp[cpu] = NULL;
-
 #else
 	/* UP is simple... */
 	if (in_xmon) {
@@ -805,7 +804,10 @@ cmds(struct pt_regs *excp)
 			break;
 		case 'x':
 		case 'X':
+			return cmd;
 		case EOF:
+			printf(" <no input ...>\n");
+			mdelay(2000);
 			return cmd;
 		case '?':
 			printf(help_string);