Let the programmer driver decide how to do AAI transfers

Currently spi_aai_write() is implemented without an abstraction
mechanism for the programmer driver. This adds another function
pointer 'write_aai' to struct spi_programmer, which is set to
default_spi_write_aai (renamed spi_aai_write) for all programmers
for now.

A patch which utilises this abstraction in the dediprog driver will
follow.

Corresponding to flashrom svn r1543.

Signed-off-by: Nico Huber <nico.huber@secunet.com>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/serprog.c b/serprog.c
index 65539a1..90ece9c 100644
--- a/serprog.c
+++ b/serprog.c
@@ -313,6 +313,7 @@
 	.multicommand	= default_spi_send_multicommand,
 	.read		= serprog_spi_read,
 	.write_256	= default_spi_write_256,
+	.write_aai	= default_spi_write_aai,
 };
 
 static void serprog_chip_writeb(const struct flashctx *flash, uint8_t val,