ALSA: usb-audio: Simplify hw_params rules

Several hw_params functions narrows the interval via min/max rule in
the very similar way, so factor out those into a helper function and
use commonly.

No functional changes, just minor code refactoring.

Tested-by: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-12-tiwai@suse.de


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