pimd: Create ability to modify hell and hold timers per interface

Create new per interface command:
'ip pim hello <1-180> {<1-180>}'

The first number is the Hello Timer for this interface
The second number is the Hold Timer to pass to neighbors on this interface.
The second number is optional.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/pimd/pim_cmd.h b/pimd/pim_cmd.h
index 25e2444..a1cb581 100644
--- a/pimd/pim_cmd.h
+++ b/pimd/pim_cmd.h
@@ -30,6 +30,9 @@
 #define CONF_SSMPINGD_STR                      "Enable ssmpingd operation\n"
 #define SHOW_SSMPINGD_STR                      "ssmpingd operation\n"
 #define IFACE_PIM_STR                          "Enable PIM SSM operation\n"
+#define IFACE_PIM_HELLO_STR                    "Hello Interval\n"
+#define IFACE_PIM_HELLO_TIME_STR               "Time in seconds for Hello Interval\n"
+#define IFACE_PIM_HELLO_HOLD_STR               "Time in seconds for Hold Interval\n"
 #define IFACE_IGMP_STR                         "Enable IGMP operation\n"
 #define IFACE_IGMP_QUERY_INTERVAL_STR          "IGMP host query interval\n"
 #define IFACE_IGMP_QUERY_MAX_RESPONSE_TIME_STR      "IGMP max query response value (seconds)\n"