ALSA: usb-audio: fix sign unintended sign extension on left shifts

ALSA: usb-audio: fix sign unintended sign extension on left shifts

commit 2acf5a3e6e9371e63c9e4ff54d84d08f630467a0 upstream.

There are a couple of left shifts of unsigned 8 bit values that
first get promoted to signed ints and hence get sign extended
on the shift if the top bit of the 8 bit values are set. Fix
this by casting the 8 bit values to unsigned ints to stop the
unintentional sign extension.

Addresses-Coverity: ("Unintended sign extension")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>