Thermal/procfs: Disabled immediately after enabling.

When exec "echo 1 > /proc/thermal/cpu-thermal", procfs get "\n" after "1", treat as disable:
```
 #1  0x000000000040f452 in thermal_procfs_write (filep=0x7ffff3d241e8, buffer=0x7ffff3d344fc "\n", buflen=1) at thermal/thermal_procfs.c:179
```

Signed-off-by: wangjianyu3 <wangjianyu3@xiaomi.com>

Author: JianyuWang0623

drivers/thermal/thermal_procfs.c

@@ -174,7 +174,15 @@ static ssize_t thermal_procfs_write(FAR struct file *filep,
 {
   FAR struct thermal_procfs_s *p = filep->f_priv;
 
-  thermal_zone_enable(p->zdev, atoi(buffer) ? true : false);
+  if (!strncmp(buffer, "1", 1))
+    {
+      thermal_zone_enable(p->zdev, true);
+    }
+  else if (!strncmp(buffer, "0", 1))
+    {
+      thermal_zone_enable(p->zdev, false);
+    }
+
   return buflen;
 }