powercap: sscanf return value error handling

Inconsistent error handling for sscanf() return value check. It uses implicit boolean conversion instead of explicit return value check. The code checks if (!sscanf(...)) which is incorrect because:
1. sscanf returns the number of successfully parsed items
2. On success, it returns 1 (one item passed)
3. On failure, it returns 0 or EOF
4. The check 'if (!sscanf(...))' is wrong because it treats success (1) as failure

All occurrences of sscanf() now uses explicit return value check. With this behavior it returns '-EINVAL' when parsing fails (returns 0 or EOF), and continues when parsing succeeds (returns 1).

Signed-off-by Sumeet Pawnikar <[email protected]>

---
 drivers/powercap/powercap_sys.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

drivers/powercap/powercap_sys.c +2 -2

index bdc65e040d17..e998454e4bf6 100644
@@ -68,7 +68,7 @@ static ssize_t show_constraint_##_attr(struct device *dev, \
        int id; \
        struct powercap_zone_constraint *pconst;\
        \
-       if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
+       if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \
                return -EINVAL; \
        if (id >= power_zone->const_id_cnt)     \
                return -EINVAL; \

@@ -93,7 +93,7 @@ static ssize_t store_constraint_##_attr(struct device *dev,\
        int id; \
        struct powercap_zone_constraint *pconst;\
        \
-       if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
+       if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \
                return -EINVAL; \
        if (id >= power_zone->const_id_cnt)     \
                return -EINVAL; \