usb: musb: Make dma_controller_create __devinit

dma_controller_create is called only from musb_init_controller
which is __devint so annotate dma_controller_create also with
__devint.

fixes the warn

WARNING: vmlinux.o(.devinit.text+0x6fa8): Section mismatch in reference from the function musb_init_controller() to the function .init.text:dma_controller_create()
The function __devinit musb_init_controller() references
a function __init dma_controller_create().
If dma_controller_create is only used by musb_init_controller then
annotate dma_controller_create with a matching annotation.

Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>