PNP / ACPI: avoid garbage in resource name

Set temporary variable as 0 to avoid garbage string output from
/proc/iomem after register resources and reset to PNP dev name
later.

Signed-off-by: Liu ShuoX <shuox.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>