[nvs] Add init function for Atmel 93C66 EEPROM

The 93C66 is identical to the 93C56 in programming interface and
addressing, but twice as large in data storage (4096 bits). It's
used in some RTL8185 wireless cards.

Signed-off-by: Michael Brown <mcb30@etherboot.org>

src/include/gpxe/threewire.h

 	init_at93cx6 ( device, organisation );
 }
 
+/**
+ * Initialise Atmel AT93C66 serial EEPROM
+ *
+ * @v device		SPI device
+ * @v organisation	Word organisation (8 or 16)
+ */
+static inline __attribute__ (( always_inline )) void
+init_at93c66 ( struct spi_device *device, unsigned int organisation ) {
+	device->nvs.size = ( 4096 / organisation );
+	device->address_len = ( ( organisation == 8 ) ? 9 : 8 );
+	init_at93cx6 ( device, organisation );
+}
+
 /** @} */
 
 #endif /* _GPXE_THREEWIRE_H */