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: Jason Wessel <jason.wessel@windriver.com>
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 31df170..1afeb5c 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2100,6 +2100,8 @@
 		}
 		if (!lines--)
 			break;
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
 
 		kdb_printf("%.*s\n", (int)len - 1, buf);
 	}