hwmon: (corsair-psu) fix unintentional sign extension issue

hwmon: (corsair-psu) fix unintentional sign extension issue

The shifting of the u8 integer data[3] by 24 bits to the left will
be promoted to a 32 bit signed int and then sign-extended to a
long. In the event that the top bit of data[3] is set then all
then all the upper 32 bits of a 64 bit long end up as also being
set because of the sign-extension. Fix this by casting data[3] to
a long before the shift.

Addresses-Coverity: ("Unintended sign extension")
Fixes: ce15cd2cee8b ("hwmon: add Corsair PSU HID controller driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20201105115019.41735-1-colin.king@canonical.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>