ALSA: usb-audio: Add sanity checks in UAC3 clock parsers

The UAC3 clock parser codes lack of the sanity checks for malformed
descriptors like UAC2 parser does.  Without it, the driver may lead to
a potential crash.

Fixes: 9a2fe9b8 ("ALSA: usb: initial USB Audio Device Class 3.0 support")
Tested-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
Reviewed-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>