acpi: Pass the correct device to acpi_pcib_osc

Fix a copy-and-paste error in acpi_pcib_request_feature where the
child device was passed into acpi_pcib_osc rather than the pcib
device.

Reviewed by: garga, jhb
Fixes: ba1904937d9a ("acpica: Extract _OSC parsing to a common file")
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D48285