ALSA: usb-audio: Add quirk bits for enabling/disabling generic implicit fb

For making easier to test, add the new quirk_flags bits 17 and 18 to
enable and disable the generic implicit feedback mode.  The bit 17 is
equivalent with implicit_fb=1 option, applying the generic implicit
feedback sync mode.  OTOH, the bit 18 disables the implicit fb mode
forcibly.

Link: https://lore.kernel.org/r/20220421064101.12456-1-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>