mfd: Fix omap usbhs crash when rmmoding ehci or ohci

The disabling of clocks and freeing GPIO are changed
to fix the occurrence of the crash of rmmod of ehci and ohci
drivers. The GPIOs should be freed after the spin locks are
unlocked.

Signed-off-by: Keshava Munegowda <keshava_mgowda@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Cc: stable@kernel.org
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>