platform/mellanox: mlxreg-io: Fix read access of n-bytes size attributes

commit db9cc7d6 upstream.

Fix shift argument for function rol32(). It should be provided in bits,
while was provided in bytes.

Fixes: 86148190

 ("platform/mellanox: mlxreg-io: Add support for complex attributes")
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20210927142214.2613929-3-vadimp@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>