The OPAL calls are returning int64_t values, which the sysparam code
stores in an int, and the sysfs callback returns ssize_t. Make code a
easier to read by consistently using ssize_t.
Signed-off-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>