usb: musb: fix some runtime_pm issues

When runtime_pm was originally added, it was done in rather confusing
way: omap2430_musb_init() (called from musb_init_controller) would do
runtime_pm_get_sync() and musb_init_controller() itself would do
runtime_pm_put to balance it out. This is not only confusing but also
wrong if non-omap2430 glue layer is used.

This confusion resulted in commit 772aed45 "usb: musb: fix
pm_runtime mismatch", that removed runtime_pm_put() from
musb_init_controller as that looked unbalanced, and also happened to
fix unrelated isp1704_charger crash. However this broke runtime PM
functionality (musb is now always powered, even without gadget active).

Avoid these confusing runtime pm dependences by making
musb_init_controller() and omap2430_musb_init() do their own runtime
get/put pairs; also cover error paths. Remove unneeded runtime_pm_put
in omap2430_remove too. isp1704_charger crash that motivated
772aed45

 will be fixed by following patch.

Cc: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>