ALSA: usb-audio: simplify set_sync_ep_implicit_fb_quirk

commit 103e9625647ad74d201e26fb74afcd8479142a37 upstream

Signed-off-by: Alberto Aguirre <albaguirre@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>