media: tw5864: Replace deprecated PCI functions

pcim_iomap_table() and pcim_iomap_regions() have been deprecated.
pcim_iomap_regions(), furthermore, has so far wrongly been passed the
device's name instead of the driver's name, which makes that function's
debug prints useless.

Replace the deprecated function with pcim_iomap_region().

Define the driver name globally and use it where appropriate.

Signed-off-by: Philipp Stanner <phasta@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>