drm/amdgpu: Release VFCT ACPI table reference

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Release VFCT ACPI table reference amdgpu_acpi_vfct_bios() fetches the VFCT table with acpi_get_table() but never releases it. acpi_get_table() takes a reference on the table (incrementing its validation_count and mapping it on the 0->1 transition); without a paired acpi_put_table() the mapping is leaked on every call, whether or not a matching VBIOS image is found. Route all exit paths after the table is acquired through a common acpi_put_table(). The VBIOS image is copied out with kmemdup() before the table is released, so it remains valid for the caller. (cherry picked from commit ca5988682b4cba4cd125a0fa99b2de1239164ae4)