usb: musb: core: print new line in the driver banner again

Commit 5c8a86e1 (usb: musb: drop unneeded
musb_debug trickery) erroneously removed '\n' from the driver's banner.
Concatenate all the banner substrings while adding it back...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Felipe Balbi <balbi@ti.com>