usb: gadget: f_uac2: Fix incorrect setting of bNumEndpoints

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.

Fixes: eaf6cbe09920 ("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>