usb: gadget: Add snapshot of CCID function driver

This USB CCID function driver will be a transport layer between
the userspace CCID component and the Windows Host. Data and control
commands from the Windows Host will be sent to the userspace
component and vice-versa.

This snapshot is taken as of commit 4f7918fd623f ("usb: f_gsi: Use
required RNDIS IAD descriptors with full speed descriptors").

Registering a misc device is discouraged, particularly when
MISC_DYNAMIC_MINOR is used as there are a limited (64) number
of dynamic minors available and can quickly exhaust. Convert
f_ccid's usage to struct cdev instead and also fix other trivial
checkpatch warnings.

Change-Id: Ie5eeda1550ac30cac47fd3799021598eac550652
Signed-off-by: Jack Pham <jackp@codeaurora.org>