regulator: lp3972: Silence uninitialized variable warning

This is harmless but my static checker complains that "tmp" is
uninitialized if lp3972_i2c_read() fails. I have moved the line of code
below the error handling to silence the warning.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/lp3972.c

···
 	mutex_lock(&lp3972->io_lock);
 
 	ret = lp3972_i2c_read(lp3972->i2c, reg, 1, &tmp);
-	tmp = (tmp & ~mask) | val;
 	if (ret == 0) {
+		tmp = (tmp & ~mask) | val;
 		ret = lp3972_i2c_write(lp3972->i2c, reg, 1, &tmp);
 		dev_dbg(lp3972->dev, "reg write 0x%02x -> 0x%02x\n", (int)reg,
 			(unsigned)val & 0xff);