ALSA: firewire-tascam: check intermediate state of clock status and retry

ALSA: firewire-tascam: check intermediate state of clock status and retry

2 bytes in MSB of register for clock status is zero during intermediate
state after changing status of sampling clock in models of TASCAM FireWire
series. The duration of this state differs depending on cases. During the
state, it's better to retry reading the register for current status of
the clock.

In current implementation, the intermediate state is checked only when
getting current sampling transmission frequency, then retry reading.
This care is required for the other operations to read the register.

This commit moves the codes of check and retry into helper function
commonly used for operations to read the register.

Fixes: 624b89df2fd7 ("ALSA: firewire-tascam: add PCM functionality")
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20190910135152.29800-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>