usb: musb: fix sparse warnings

The following warnings are fixed:

drivers/usb/musb/musb_core.c:357:6: warning: symbol 'musb_otg_timer_func' was not declared. Should it be static?
drivers/usb/musb/musb_core.c:1339:27: warning: incorrect type in initializer (different address spaces)
drivers/usb/musb/musb_core.c:1339:27:    expected void *mbase
drivers/usb/musb/musb_core.c:1339:27:    got void [noderef] <asn:2>*mregs
drivers/usb/musb/musb_core.c:1347:17: warning: incorrect type in argument 1 (different address spaces)
drivers/usb/musb/musb_core.c:1347:17:    expected void [noderef] <asn:2>*addr
drivers/usb/musb/musb_core.c:1347:17:    got void *mbase
drivers/usb/musb/musb_core.h:487:27: warning: incorrect type in initializer (different address spaces)
drivers/usb/musb/musb_core.h:487:27:    expected void *mbase
drivers/usb/musb/musb_core.h:487:27:    got void [noderef] <asn:2>*mregs
drivers/usb/musb/musb_core.h:491:26: warning: incorrect type in argument 1 (different address spaces)
drivers/usb/musb/musb_core.h:491:26:    expected void const [noderef] <asn:2>*addr
drivers/usb/musb/musb_core.h:491:26:    got void *mbase
drivers/usb/musb/tusb6010.c:270:48: warning: incorrect type in argument 2 (different address spaces)
drivers/usb/musb/tusb6010.c:270:48:    expected void [noderef] <asn:2>*buf
drivers/usb/musb/tusb6010.c:270:48:    got unsigned char [usertype] *[assigned] buf
drivers/usb/musb/tusb6010.c:164:32: warning: incorrect type in argument 1 (different address spaces)
drivers/usb/musb/tusb6010.c:164:32:    expected void *to
drivers/usb/musb/tusb6010.c:164:32:    got void [noderef] <asn:2>*buf
drivers/usb/musb/tusb6010.c:172:24: warning: incorrect type in argument 1 (different address spaces)
drivers/usb/musb/tusb6010.c:172:24:    expected void *to
drivers/usb/musb/tusb6010.c:172:24:    got void [noderef] <asn:2>*[assigned] buf

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