UPSTREAM: usb: gadget: f_uac2: Fix incorrect setting of bNumEndpoints

Currently afunc_bind sets std_ac_if_desc.bNumEndpoints to 1 if
controls (mute/volume) are enabled. During next afunc_bind call,
bNumEndpoints would be unchanged and incorrectly set to 1 even
if the controls aren't enabled.

Fix this by resetting the value of bNumEndpoints to 0 on every
afunc_bind call.

Bug: 254441685
Fixes: eaf6cbe0 ("usb: gadget: f_uac2: add volume and mute support")
Cc: stable <stable@kernel.org>
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/20241211115915.159864-1-quic_prashk@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 057bd54d)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I1da43996d35411850984b6a9a9f79ef4dc63b5b5