V4L/DVB (8020): Fix callbacks functions of saa7134_empress

V4L/DVB (8020): Fix callbacks functions of saa7134_empress

If I try v4l2-ctl --all -d /dev/video1 or v4l2-ctl --streamon -d /dev/video1
modules crashed:

*pde = 00000000
Modules linked in: ac battery loop saa7134_empress(F) saa6752hs(F) tuner_simple(F) tuner_types(F) tea5767(F) tda9887(F) tda8290(F) tea5761(F) tuner(F) snd_cmipci snd_pcm snd_page_alloc snd_opl3_lib saa7134(F) snd_mpu401 parport_pc parport snd_timer snd_hwdep snd_mpu401_uart floppy rtc psmouse videodev(F) v4l1_compat(F) compat_ioctl32(F) v4l2_common(F) videobuf_dma_sg(F) videobuf_core(F) snd_rawmidi snd_seq_device via_ircc pcspkr snd ir_kbd_i2c(F) irda soundcore ir_common(F) crc_ccitt tveeprom(F) i2c_viapro i2c_core button via_agp agpgart evdev ext3 jbd mbcache ide_cd_mod cdrom ide_disk 8139cp via82cxxx ide_core 8139too mii ehci_hcd uhci_hcd usbcore thermal processor fan

EIP is at __mutex_lock_slowpath+0x29/0x7b
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process v4l2-ctl (pid: 2742, ti=ced7e000 task=cf325260 task.ti=ced7e000)
       d08e5411 00000000 ced7fed4 00000000 d0975acb 40045612 cfa86ee0 ffffffcd
       cf2b7000 ced7febc c03858d6 00000019 00000292 d089e4ec cf37b2a0 d089e4a0
Call Trace:
 [<c028b52b>] mutex_lock+0xa/0xb
 [<d08e5411>] videobuf_streamon+0xf/0x9a [videobuf_core]
 [<d0975acb>] __video_do_ioctl+0x136a/0x2d68 [videodev]
 [<d088f789>] task_end_request+0x40/0x51 [ide_core]
 [<d088c4aa>] ide_intr+0x187/0x192 [ide_core]
 [<c016a551>] mntput_no_expire+0x11/0x64
 [<c0160b1c>] path_walk+0x90/0x98
 [<d0977738>] video_ioctl2+0x173/0x239 [videodev]
 [<c0140936>] filemap_fault+0x202/0x370
 [<c014930a>] __do_fault+0x2c3/0x2fe
 [<c014ab03>] handle_mm_fault+0x22a/0x49f
 [<c0162737>] vfs_ioctl+0x47/0x5d
 [<c0162992>] do_vfs_ioctl+0x245/0x258
 [<c01629e6>] sys_ioctl+0x41/0x5b
 [<c01036a6>] sysenter_past_esp+0x5f/0x85
 =======================

After this fix all of that commands works without problem:

v4l2-ctl --all -d /dev/video1

Driver Info:
	Driver name   : saa7134
	Card type     : Beholder BeholdTV M6 Extra
	Bus info      : PCI:0000:00:0d.0
	Driver version: 526
	Capabilities  : 0x05000001
		Video Capture
		Read/Write
		Streaming
Format Video Capture:
	Width/Height  : 720/576
	Pixel Format  : MPEG
	Field         : Any
	Bytes per Line: 0
	Size Image    : 58656
	Colorspace    : Unknown (00000000)
Video input : 0 (CCIR656)
Video Standard = 0x000000ff
	PAL-B/B1/G/H/I/D/D1/K

P.S. data from /dev/video1 is not correct :(( .

Signed-off-by: Beholder Intl. Ltd. Dmitry Belimov <d.belimov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>