acpi_wmi: Add type check before evaluaeting query ACPI method
Some ACPI wmi query is implemented by named object, not method,
ACPICA complains when non-method object is evaluated with one or more arguments.
Especially, almost all binary MOF object obtaining method is the case.

This commit will fix it.

PR: 284912
Reported by: Alexander Ziaee
Differential Revision: https://reviews.freebsd.org/D49129