mxser: pci, switch to managed resources

Switch to managed resources for PCI using pcim_enable_device.
Regions and device disabling is now taken care of by the core and we
need not unwind. Neither in ->probe, nor in ->remove. That simplifies
the code.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210618061516.662-46-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>