ALSA: usb: fcp: Fix meter_levels type to __le32

The cached level meter values are returned from the USB core as
__le32, hence declare properly.

Fixes: 46757a3e ("ALSA: FCP: Add Focusrite Control Protocol driver")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501212331.SaePSmsA-lkp@intel.com/
Link: https://patch.msgid.link/20250121170032.7236-2-tiwai@suse.de


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