Named semaphores:  Bad cast in sem_close().  Fixed by reordering fields of struct nsem_inode_s so that the cast will work

Improvements of AT24xx MTD driver

Signed-off-by: Marten Svanfeldt <marten@intuitiveaerial.com>

These parts utilize the same one-byte-address in the I2C protocol as the -02,
but requires different I2C addresses for different banks of the EEPROM.

Signed-off-by: Marten Svanfeldt <marten@intuitiveaerial.com>

Buttons lower half:  Undefine __KERNEL__ before including board.h to suppress bad included; fix some configuratin issues