That patch fixes handling SPI messages with two writing transfers. It's
important when using e.g. by m25p80 driver which uses one transfer for
opcode and another one for data.
Thanks to that fix we can now drop m25p80 workaround patch. It means one
less hack and also a better flash writing performance as there is no
more data buf copying.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
