rtc: pcf2127: fix pcf2127_nvmem_read/write() returns

These functions should return zero on success.  Non-zero returns are
treated as error.  On some paths, this doesn't matter but in
nvmem_cell_read() a non-zero return would be passed to ERR_PTR() and
lead to an Oops.

Fixes: d6c3029f ("rtc: pcf2127: add support for accessing internal static RAM")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201022070451.GA2817669@mwanda

drivers/rtc/rtc-pcf2127.c

@@ -243,10 +243,8 @@ static int pcf2127_nvmem_read(void *priv, unsigned int offset,
 	if (ret)
 		return ret;
 
-	ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
-			       val, bytes);
-
-	return ret ?: bytes;
+	return regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
+				val, bytes);
 }
 
 static int pcf2127_nvmem_write(void *priv, unsigned int offset,
@@ -261,10 +259,8 @@ static int pcf2127_nvmem_write(void *priv, unsigned int offset,
 	if (ret)
 		return ret;
 
-	ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
-				val, bytes);
-
-	return ret ?: bytes;
+	return regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
+				 val, bytes);
 }
 
 /* watchdog driver */