package/libv4l: add missing bpf_common.h header

package/libv4l: add missing bpf_common.h header

Fixes [1] (for older toolchains not providing this header):

    CC       keytable.o
  In file included from bpf.h:26:0,
                   from keytable.c:37:
  ../../include/linux/bpf.h:12:10: fatal error: linux/bpf_common.h: No such file or directory
   #include <linux/bpf_common.h>
            ^~~~~~~~~~~~~~~~~~~~

[1] http://autobuild.buildroot.org/results/d22c0939eed4bc949f7eaeae7595d01ec45cc2cd

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>