media: pci/ivtv: Replace ioremap with devm_ variants

With Managed Device Resources the error handling is simpler.

The following smatch warning is silenced:
drivers/media/pci/ivtv/ivtv-driver.c: drivers/media/pci/ivtv/ivtv-driver.c:1296 ivtv_probe() warn: 'itv->dec_mem' from ioremap() not released on lines: 1296.
drivers/media/pci/ivtv/ivtv-driver.c: drivers/media/pci/ivtv/ivtv-driver.c:1296 ivtv_probe() warn: 'itv->enc_mem' from ioremap() not released on lines: 1296.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>