Kill central list of SPI programmers

Remove the array spi_programmer, replace it by dynamic registration
instead. Also initially start with no busses supported, and switch to
the default non-SPI only for the internal programmer.

Also this patch changes the initialization for the buses_supported variable
from "everything-except-SPI" to "nothing". All programmers have to set the
bus type on their own, and this enables register_spi_programmer to just add
the SPI both for on-board SPI interfaces (where the internal programmer
already detected the other bus types), as well as for external programmers
(where we have the default "none").

Corresponding to flashrom svn r1299.

Signed-off-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/spi25.c b/spi25.c
index c9e1ebf..b3bd7a1 100644
--- a/spi25.c
+++ b/spi25.c
@@ -178,7 +178,7 @@
 	/* Some SPI controllers do not support commands with writecnt=1 and
 	 * readcnt=4.
 	 */
-	switch (spi_controller) {
+	switch (spi_programmer->type) {
 #if CONFIG_INTERNAL == 1
 #if defined(__i386__) || defined(__x86_64__)
 	case SPI_CONTROLLER_IT87XX:
@@ -1351,7 +1351,7 @@
 		.readarr	= NULL,
 	}};
 
-	switch (spi_controller) {
+	switch (spi_programmer->type) {
 #if CONFIG_INTERNAL == 1
 #if defined(__i386__) || defined(__x86_64__)
 	case SPI_CONTROLLER_IT87XX: