package/dahdi-linux: needs CRC CCITT

dahdi-linux needs a linux with CRC CCITT since the addition of the
package in commit d959966b41bd88a36664c733a8a8d2b6809e4fc2 as stated in
the README:

- CONFIG_CRC_CCITT must be enabled ('y' or 'm'). On 2.6 kernels this can
  be selected These can be selected from the "Library Routines" submenu
  during kernel configuration via "make menuconfig".

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit b22ec4bd95b7d9dd82990937e6488ca7136e6136)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/dahdi-linux/dahdi-linux.mk

@@ -60,6 +60,10 @@ define DAHDI_LINUX_EXTRACT_FW
 endef
 DAHDI_LINUX_POST_EXTRACT_HOOKS += DAHDI_LINUX_EXTRACT_FW
 
+define DAHDI_LINUX_LINUX_CONFIG_FIXUPS
+	$(call KCONFIG_ENABLE_OPT,CONFIG_CRC_CCITT)
+endef
+
 # Need to pass the same options as for building the modules, because
 # it wants to scan Linux' .config file to check whether some options
 # are set or not (like CONFIG_FW_LOADER).