misc: eeprom: max6875: clean up max6875_read()

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

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>