ALSA: usb-audio: Add helper function for volume range checks

ALSA: usb-audio: Add helper function for volume range checks

When a potentially insane volume range is found, the volume control
parameters will be printed in WARN level instead of DEBUG level.
Currently, it's done by emitting a open-coded usb_audio_warn() in the
corresponding check.

The following changes are about to add more checks against volumen
ranges. As the first step, extract the current check logic into a helper
function to improve readability.

No functional change intended.

Signed-off-by: Rong Zhang <i@rong.moe>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260303194805.266158-3-i@rong.moe