misc: pvpanic: Check devm_ioport_map() for NULL

misc: pvpanic: Check devm_ioport_map() for NULL

Inconveniently devm_ioport_map() and devm_ioremap_resource()
return errors differently, i.e. former uses simply NULL pointer,
while the latter an error pointer.

Due to this, we have to check each of them separately.

Fixes: f104060813fe ("misc: pvpanic: Combine ACPI and platform drivers")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20201228184313.57610-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>