linux-headers: bump 4.{9, 14}.x series

[Peter: drop 4.14.x bump]
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit e4bdd2a8241eb0c3b6e2634c2b693a743e99cec8)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/linux-headers/Config.in.host

@@ -245,7 +245,7 @@ config BR2_DEFAULT_KERNEL_HEADERS
 	default "3.12.74"	if BR2_KERNEL_HEADERS_3_12
 	default "4.1.48"	if BR2_KERNEL_HEADERS_4_1
 	default "4.4.108"	if BR2_KERNEL_HEADERS_4_4
-	default "4.9.72"	if BR2_KERNEL_HEADERS_4_9
+	default "4.9.73"	if BR2_KERNEL_HEADERS_4_9
 	default "4.10.17"	if BR2_KERNEL_HEADERS_4_10
 	default "4.11.12"	if BR2_KERNEL_HEADERS_4_11
 	default "4.12.14"	if BR2_KERNEL_HEADERS_4_12