driver core: make device_is_dependent() static

driver core: make device_is_dependent() static

The function device_is_dependent() is only called by the driver core
internally and should not, at this time, be called by anyone else
outside of it, so mark it as static so as not to give driver authors the
wrong idea.

Cc: Saravana Kannan <saravanak@google.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/2023112815-faculty-thud-add8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>