ANDROID: usb: f_accessory: Avoid bitfields for shared variables

Using bitfields for shared variables is a "bad idea", as they require
a non-atomic read-modify-write to be generated by the compiler, which can
cause updates to unrelated bits in the same word to disappear.

Ensure the 'online' and 'disconnected' members of 'struct acc_dev' are
placed in separate variables by declaring them each as 'int'.

Bug: 173789633
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Ia6031d82a764e83b2cc3502fbe5fb273511da752
Signed-off-by: Giuliano Procida <gprocida@google.com>