rt2x00: Streamline rt2800 eeprom initialisations.

In rt2800lib.c the rt2800_init_eeprom function the same eeprom
words were read multiple times, due to inefficient ordering of the
eeprom checks.

Reorder the checks so that each EEPROM word only has to be read once.

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>