rtc: isl1208: Fix return value of nvmem callbacks

Read/write callbacks registered with nvmem core expect 0 to be returned
on success and a negative value to be returned on failure.

isl1208_nvmem_read()/isl1208_nvmem_write() currently return the number of
bytes read/written on success, fix to return 0 on success and negative on
failure.

Fixes: c3544f6f ("rtc: isl1208: Add new style nvmem support to driver")
Cc: stable@vger.kernel.org
Signed-off-by: Joy Chakraborty <joychakr@google.com>
Link: https://lore.kernel.org/r/20240612080831.1227131-1-joychakr@google.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-isl1208.c

@@ -775,14 +775,13 @@ static int isl1208_nvmem_read(void *priv, unsigned int off, void *buf,
 {
 	struct isl1208_state *isl1208 = priv;
 	struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
-	int ret;
 
 	/* nvmem sanitizes offset/count for us, but count==0 is possible */
 	if (!count)
 		return count;
-	ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1 + off, buf,
+
+	return isl1208_i2c_read_regs(client, ISL1208_REG_USR1 + off, buf,
 				    count);
-	return ret == 0 ? count : ret;
 }
 
 static int isl1208_nvmem_write(void *priv, unsigned int off, void *buf,
@@ -790,15 +789,13 @@ static int isl1208_nvmem_write(void *priv, unsigned int off, void *buf,
 {
 	struct isl1208_state *isl1208 = priv;
 	struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
-	int ret;
 
 	/* nvmem sanitizes off/count for us, but count==0 is possible */
 	if (!count)
 		return count;
-	ret = isl1208_i2c_set_regs(client, ISL1208_REG_USR1 + off, buf,
-				   count);
 
-	return ret == 0 ? count : ret;
+	return isl1208_i2c_set_regs(client, ISL1208_REG_USR1 + off, buf,
+				   count);
 }
 
 static const struct nvmem_config isl1208_nvmem_config = {