usb: gadget: tcm: split string definitions into function and device

Prepare for factoring out f_tcm from a legacy gadget.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2 files changed