power: qcom_smbb: test the correct variable

"state" is a bool so it's never less than zero.  The intent was to test
"ret" instead.

Fixes: 56d7df87 ('power: Add Qualcomm SMBB driver')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>