usb: gadget: Handle function control requests before set config

some function drivers receive control requests before configuration is
selected, which are not being handled due to configuratiopn checks in
android gadget driver, which is resulting in stall on control endpoint.
Fix this issue, by removing the configuration checks, so that function
driver control requests are handled properly.

Change-Id: I90975bb6a7c0201de7715932469c603fea6954af
Signed-off-by: Chiranjeevi Velempati <cvelempa@codeaurora.org>
Signed-off-by: Iliyan Malchev <malchev@google.com>