uio/uio_pci_generic: use device-managed function equivalents

This driver can be easily converted to use the device-managed allocator
function and the PCI managed enable function.

With these conversions the probe error paths are no longer needed and
neither is the remove function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201111113828.64992-1-alexandru.ardelean@analog.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>