V4L/DVB (7802): tuner: Failures at tuner_attach were producing OOPS

As reported by Mike Galbraith <efault@gmx.de>:

[   13.666587] TUNER: Unable to find symbol tda829x_probe()
[   13.674638] tuner' 1-004b: chip found @ 0x96 (saa7133[0])
[   13.691175] DVB: Unable to find symbol tda9887_attach()
[   13.698968] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[   13.709509] IP: [<ffffffff80302934>] strlcpy+0x11/0x36
[   13.711135] PGD be167067 PUD be140067 PMD 0
[   13.711137] Oops: 0000 [1] SMP

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>