We can't check for the ACPI table revision validity in the same if
where we check if the package was read correctly, because we return
PTR_ERR(pkg) and if the table is not valid but the pointer is, we
would return a valid pointer as an error.  Fix that by moving the
table checks to a separate if and return -EINVAL if it's not valid.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>