usb: gadget: nokia: use function framework for ACM

This patch converts the acm_ms gadget to make use of the function
framework to request the ACM function.

The "old" include interface for acm is now removed since nokia was the
last user of it (for ACM).

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>