ANDROID: fix up rndis ABI breakage

Commit XXX broke the rndis abi by adding a lock to the device structure.
This is the correct thing to do, to resolve an issue, but work around
this by moving the lock to be a one-lock-per-driver instead of a
per-device lock.  This matches the first submission of this commit, so
it still resolves the same problem, while preserving the ABI for now.

Bug: 161946584
Fixes: 9ab652d4 ("usb: gadget: rndis: add spinlock for rndis response list")
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I7c4d32524b7b10f23a15be35f762b1ed9f345b95