usb: core: of.c: fix defined but not declare warning

The helper usb_of_get_child_node is defined at of.c, but missing its
declare as a global function. Fix it by adding related header file
as well as compile it on conditional of CONFIG_OF.

Cc: Greg Kroah-Hartman <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Ben Dooks <[email protected]>
Cc: [email protected]

Signed-off-by: Peter Chen <[email protected]>
Reported-by: Ben Dooks <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions