PCI: vmd: Use devm_kasprintf() instead of simple kasprintf()

Use devm_kasprintf() instead of simple kasprintf() to free allocated memory
automatically when the device is freed.

Suggested-by: Srikanth Thokala <srikanth.thokala@intel.com>
Link: https://lore.kernel.org/r/20220531132617.20517-1-subramanian.mohan@intel.com


Signed-off-by: Subramanian Mohan <subramanian.mohan@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Nirmal Patel <nirmal.patel@linux.intel.com>