[PATCH] hwmon: soften lm75 initialization

The LM75 initialization is a bit agressive, it arbitrarily reconfigures
the chip. Make it only change the bit it needs. This is a port from
the 2.4 kernel version of the driver (lm_sensors).

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>