rtc: ds1553: clean up ds1553_nvram_read()/ds1553_nvram_write()

The change removes redundant sysfs binary file boundary checks, since
this task is already done on caller side in fs/sysfs/file.c

Signed-off-by: Vladimir Zapolskiy <[e-mail]>
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-ds1553.c

···
 	void __iomem *ioaddr = pdata->ioaddr;
 	ssize_t count;
 
-	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
+	for (count = 0; count < size; count++)
 		*buf++ = readb(ioaddr + pos++);
 	return count;
 }
···
 	void __iomem *ioaddr = pdata->ioaddr;
 	ssize_t count;
 
-	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
+	for (count = 0; count < size; count++)
 		writeb(*buf++, ioaddr + pos++);
 	return count;
 }