sony-laptop: fix a couple signedness bugs

This needs to be signed to handle negative error codes.
Remove a redundant check, read_limits is always called with a valid
handle.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/sony-laptop.c

@@ -2139,7 +2139,7 @@ static ssize_t sony_nc_thermal_mode_show(struct device *dev,
 		struct device_attribute *attr, char *buffer)
 {
 	ssize_t count = 0;
-	unsigned int mode = sony_nc_thermal_mode_get();
+	int mode = sony_nc_thermal_mode_get();
 
 	if (mode < 0)
 		return mode;
@@ -2507,8 +2507,6 @@ static void sony_nc_backlight_ng_read_limits(int handle,
 	props->maxlvl = 0xff;
 
 	offset = sony_find_snc_handle(handle);
-	if (offset < 0)
-		return;
 
 	/* try to read the boundaries from ACPI tables, if we fail the above
 	 * defaults should be reasonable