Please apply commits f0f1b8cac4d8 and 7fafcfdf6377 to v4.4.y

[Guenter Roeck <linux@xxxxxxxxxxxx>]

Commit 7fafcfdf6377 ("USB: gadget: f_midi: fixing a possible double-free in f_midi")
fixes CVE-2018-20961. Commit f0f1b8cac4d8 ("usb: gadget: f_midi: fail if set_alt fails
to allocate requests") avoids a context conflict when applying 7fafcfdf6377,
and fixes another minor problem.

Commit 7fafcfdf6377 is present in v4.9.y and v4.14.y.

Thanks,
Guenter