usb: mtu3: fix ssusb_wakeup_set dummy

Changing from ssusb_wakeup_enable/disable to ssusb_wakeup_set was done
in only one of two places in the kernel, the other one now causes a
build failure:

drivers/usb/mtu3/mtu3_plat.c: In function 'mtu3_suspend':
drivers/usb/mtu3/mtu3_plat.c:462:2: error: implicit declaration of function 'ssusb_wakeup_set'; did you mean 'ssusb_wakeup_disable'? [-Werror=implicit-function-declaration]

This adapts the dummy helpers the same way that the extern declarations
were.

Fixes: f0ede2c6 ("usb: mtu3: supports remote wakeup for mt2712 with two SSUSB IPs")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>