[media] davinci: vpbe: fix module build

[media] davinci: vpbe: fix module build

add a null entry in platform_device_id {}.
This patch fixes following error:
drivers/media/platform/davinci/vpbe_venc: struct platform_device_id is 24 bytes.  The last of 3 is:
0x64 0x6d 0x33 0x35 0x35 0x2c 0x76 0x70 0x62 0x65 0x2d 0x76 0x65 0x6e 0x63 0x00 0x00 0x00 0x00 0x00 0x03 0x00 0x00 0x00
FATAL: drivers/media/platform/davinci/vpbe_venc: struct platform_device_id is not terminated with a NULL entry!
make[1]: *** [__modpost] Error 1

Reported-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>