kdb: Fix dmesg/bta scroll to quit with 'q'

If you press 'q' the pager should exit instead of printing everything
from dmesg which can really bog down a 9600 baud serial link.

The same is true for the bta command.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

kernel/debug/kdb/kdb_bt.c

@@ -129,6 +129,8 @@ kdb_bt(int argc, const char **argv)
 		}
 		/* Now the inactive tasks */
 		kdb_do_each_thread(g, p) {
+			if (KDB_FLAG(CMD_INTERRUPT))
+				return 0;
 			if (task_curr(p))
 				continue;
 			if (kdb_bt1(p, mask, argcount, btaprompt))

kernel/debug/kdb/kdb_main.c

@@ -2100,6 +2100,8 @@ static int kdb_dmesg(int argc, const char **argv)
 		}
 		if (!lines--)
 			break;
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
 
 		kdb_printf("%.*s\n", (int)len - 1, buf);
 	}