PCI/ACPI: Fix allocated memory release on error in pci_acpi_scan_root()

In the pci_acpi_scan_root() function, when creating a PCI bus fails,
we need to free up the previously allocated memory, which can avoid
invalid memory usage and save resources.

Fixes: 789befdf ("arm64: PCI: Migrate ACPI related functions to pci-acpi.c")
Signed-off-by: Zhe Qiao <qiaozhe@iscas.ac.cn>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20250430060603.381504-1-qiaozhe@iscas.ac.cn