comedi: s526: Add sanity checks for I/O base address

comedi: s526: Add sanity checks for I/O base address

The "s526" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of a Sensoray
526 board.  It currently allows any base address to be configured but
the hardware only supports base addresses (configured by on-board DIP
switches) in the range 0 to 0xFFC0 on 64-byte boundaries.

Add a sanity check to ensure the device is not configured at an
unsupported base address.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260130170416.49994-47-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>