usb: musb-new: Fix improper musb host pointer

usb: musb-new: Fix improper musb host pointer

When MUSB is operating in peripheral mode, probe registering
musb core using musb_register which intern return int value
for validation. so there is no scope to preserve struct musb
pointer but the same can be used in .remove musb_stop.
So fix this by return musb_register with struct musb pointer.

Cc: Igor Grinberg <[email protected]>
Cc: Purna Chandra Mandal <[email protected]>
Tested-by: Chen-Yu Tsai <[email protected]> # A33-OlinuXino
Tested-by: Jagan Teki <[email protected]>
Signed-off-by: Jagan Teki <[email protected]>