usb: gadget: function: Remove redundant usb_free_all_descriptors

Removed usb_free_all_descriptors in the bind functions, which
results in double-free corruption of the descriptors on error path.
The usb descriptors are allocated by usb_assign_descriptors.

Signed-off-by: Pavitrakumar Managutte <pavitra1729@gmail.com>
Reviewed-by: Robert Baldyga <r.baldyga@samsung.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>