batman-adv: Re-add kmod-lib-crc16 back to dependency line

batman-adv: Re-add kmod-lib-crc16 back to dependency line

The OpenWrt dependency builder cannot extract the crc16 dependency from
the KMOD_BATMAN_ADV_BLA dependencies. They have to be specified directly in
the OpenWrt Makefile's DEPENDS line to avoid error when BLA is enabled:

  Package kmod-batman-adv is missing dependencies for the following libraries:
  crc16.ko

Reported-by: Lech Perczak <lech.perczak@gmail.com>
Fixes: 0db66160aaab ("batman-adv: Sync config options with kernel Kconfig")
Signed-off-by: Sven Eckelmann <sven@narfation.org>