usb: gadget: f_mass_storage: create _fsg_common_free_buffers
usb: gadget: f_mass_storage: create _fsg_common_free_buffers

When configfs is in place, gadgets will have to be able to free
fsg buffers. Add a helper function.

Signed-off-by: Andrzej Pietrasiewicz <0bcd4dade8bc9135441847460b651a5ef589ec79@samsung.com>
Signed-off-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>
Acked-by: Michal Nazarewicz <605208d9b4c769ca62e9f9f8b592c9cd465fe6d7@mina86.com>
Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs