Add device data pointer to the USB gadget's device struct.
Wrapper for extracting usb_gadget from Linux's usb device

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Vasut <marex@denx.de>

Fixes most of checkpatch warnings and errors in USB gadget stack.

The most frequently encountered problems are:
1) "(foo*)", "foo * bar", "foo* bar"
2) C99 // comments
3) No spaces before/after/around '?', ':', '=', '==', ',', '&', '('
4) Spaces before '['
5) Spaces between function names and '('
6) Block braces in wrong places
7) Spaces before tabs
8) Macros with complex values not enclosed in parenthesis
9) Multiline comments start just after /*

Signed-off-by: Vitaly Kuzmichev <vkuzmichev@mvista.com>

Derived from Linux kernel 2.6.27

Signed-off-by: Thomas Smits <ts.smits@gmail.com>
Signed-off-by: Remy Bohmer <linux@bohmer.net>