USB: android: Handle composition switch failure for ACM function

Dont let usb_remove_function delete the list which is
already freed from android_bind_config failure path.

Because the number of endpoints are less on some targets,
the composition with higher number of functions may
lead to composition switch failure. In process of
handling this failure, android_bind_config
itself deletes the function from the list. Now
when ACM does the same thing in its unbind handler
via usb_remove_function, it leads to a crash.

Currently many functions dont handle unbind,
and same thing is processed from android_disable. To fix
this ACM crash, dont call usb_remove_function.

CRs-Fixed: 625177
Change-Id: I6fdab52254ddf03bd60c2c774df9a8836431d3ae
Signed-off-by: Sujeet Kumar <ksujeet@codeaurora.org>