USB: musb: fix possible panic while resuming

During driver resume processing, musb could cause a kernel panic.
Fix by enabling the clock earlier, with the resume_early method.

Signed-off-by: Kim Kyuwon <q1.kim@samsung.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>