staging: comedi: amplc_pc263: Use IS_ENABLED()

Change conditional compilation on kernel options to use the IS_ENABLED()
macro.  Remove most of the #ifdef lines and add extra if
(IS_ENABLED(xxx)) tests so the compiler can remove unreachable code.
The pci_driver stuff and device table is still conditionally compiled.

In pc263_attach() move the call to alloc_private() as it is only used
for PCI devices.  (In pc263_detach(), for ISA devices a non-zero
dev->iobase means the I/O region needs releasing.)

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>