The spi-nor write loop assumes that what is passed to the hardware
driver write() is what gets written.

When write() writes less than page size at once data is dropped on the
floor. Check the amount of data writen and exit if it does not match
requested amount.
Signed-off-by: NMichal Suchanek <hramrach@gmail.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Tested-by Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: NMichal Suchanek <hramrach@gmail.com>
Tested-by: NMichal Suchanek <hramrach@gmail.com>