CVE-2023-52680 ALSA: scarlett2: Add missing error checks to *_ctl_get()

In the Linux kernel, the following vulnerability has been resolved:

ALSA: scarlett2: Add missing error checks to *_ctl_get()

The ctl_get() functions which call scarlett2_update() were not
checking the return value. Fix to check the return value and pass to
the caller.